This post is meant to consolidate the information originally found in these threads.
MAJOR UPDATE: 4/17/12: Video of porous upper bushing in Differences Section.
UPDATE: 4/13/12: Included brief explanation video of one of the alternate designs. It's added in the Alternate Designs section under the Oil Bath.
UPDATE: 4/11/12: Included Clocking video that shows how to align the OPDA for TDC removal in the Removal Section. Big thanks to Bigbob!
UPDATE: 4/5/12: Added link to 2002 Jeep OPDA with abnormal wear. The link is in this intro post below.
UPDATE: 2/25/12: Included Oil Flow Through Design in Alternate Designs Section.
UPDATE 2/21/12: Included OPDA replacement in Q&A Section.
UPDATE 12/22/11: Included links to Shell Rotella Oil to the Oils and Grease Section.
UPDATE 12/14/11: Included new Laughing Monkey video to the Problems Section. Video provided by DME.
UPDATE 12/10/11: Included additional link to Oil Cup Alternate in the Alternate Designed section below. I recommend this over the grease fitting.
Update 9/16/11: Cleaned up the links below. Added link to newest Poll.
Update 7/12/11: Cleaned up the Q&A section and added links to help navigate the 100+ page thread.
Update 4/27/11: Included additional section. Section 11: Alternate Designs. See below for more info.
Update 2/21/11: Included link to Crown correspondence for a replacement aftermarket OPDA. http://www.jeepforum.com/forum/f9/ne.../#post11017999
Update 1/30/11: The sections below will be updated as we find more details and facts. At the top of each section I will include a BOLD Update notifier and a brief description. If you have a question regarding an update please let me know. I'm trying to make the first page easy to navigate. Also be aware that the Q&A section near the bottom will be updated with questions as I receive them. I may make small edits to conserve space, but I will like the original post in the Q&A for further review.
For those of you new to this problem, please understand that while the 2005-06 OPDA is flawed, the cam and lifter issues are wide spread over other model years. This is covered with the ZDDP and engine oil changes over the years.
And for those of you who think you're not affected, below is a link to a 1999 distributor with the laughing monkey. (though as you'll read the 2005-06 is more susceptible due to the upper bushing problem)
The fixes and modifications on this subject were a group effort from members of this forum and supporting contacts. There is only a small amount of information regarding the results of these changes. I’ll update as more information is provided.
Also, I’m not a tech guy so if there are some details that are omitted please let me know. The hope is to limit this thread to only a few pages of actual information regarding how to handle this problem.
The complete assembly is known as the Oil Pump Drive Assembly (OPDA). It may also be referred to as the Camshaft Positioning Sensor (CPS) or distributor. I will refer to it as the OPDA.
The OPDA has three components.
1. The top part of the unit is the CPS. This will include the actual sensor and the target wheel attached to the center shaft.
2. The lower portion has a helical gear that mates with the camshaft gear. The gear is known as the Oil Pump Drive Gear. The mating of these gears turns the shaft. As mentioned in item 1, the top of this shaft has the target wheel which determines the engine timing.
3. The bottom of the shaft has a flat tip that will fit into a keyway for the oil pump. As the gear spins, the shaft turns the oil pump.
2005 JEEP WRANGLER Bulletin - Vehicle Safety TSB ID 9419 NHTSA Item Number: 10013784
Service Bulletin #: 05
Vehicle/Equipment Make: JEEP
Vehicle/Eqipment Model: WRANGLER
Model Year: 2005
Mfg Component Code: 060000 ENGINE AND ENGINE COOLING
Date of Bulletin: 2005-03-01
Date Added: 2005-04-26
Summary: THE OIL PUMP DRIVE GEAR ON ABOUT 16,000 OF THE ABOVE VEHICLE MAY WEAR OUT PREMATURELY AND CAUSE ENGINE FAILURE DUE TO A LOSS OF OIL PRESSURE. *SC
(I cannot find the official source of the below info. It definitely looks legit. EDIT: A quick Internet search leads me to believe this is from a CARFAX report)
A revised drive gear parts package has been released. The second roll pin hole must be drilled in the revised drive gear.
2005 (TJ) Jeep(R) Wrangler
NOTE : This notification applies only to the above vehicles equipped with a 4.0L eligible ("S" in the 8th VIN position) and an engine build code between 902944 (October 20, 2004) and 900325 (February 1, 2005).
IMPORTANT : Some of the involved vehicles may be in dealer vehicle inventory. Dealers should complete this repair on these vehicles before retail delivery. Dealers should also perform this repair on vehicles in for service. Involved vehicles can be determined by using the VIP inquiry process.
The oil pump drive gear on about 16,000 of the above vehicles may wear out prematurely and cause engine failure due to a loss of oil pressure.
The camshaft position sensor/oil pump drive assembly date code label must be inspected. Units within a specific date code range must have the drive gear replaced.
All unsold vehicles must have the oil pump drive gear replaced prior to retail delivery to eliminate the risk of engine failure due to premature oil pump drive gear wear. On sold vehicles, the cam/crank angle must also be checked with the DRB III scan tool. Engines found with excessive cam/crank angle must have the oil pump drive gear and the engine camshaft replaced.
Dealers should attempt to minimize customer inconvenience by placing the owner in a loaner vehicle if inspection determines that an engine camshaft is required and the vehicle must be held overnight.
The Special Tools may be required to perform this service procedure.
Completion Reporting and Reimbursement
Claims for vehicles that have been serviced must be submitted on the DealerCONNECT Claim Entry Screen located on the Service tab. Claims submitted will be used by DaimlerChrysler to record Customer Satisfaction Notification service completions and provide dealer payments.
Use one of the labor operation numbers and time allowances shown.
Add the cost of the parts package plus applicable dealer allowance to your claim.
NOTE : See the Warranty Administration Manual, Recall Claim Processing Section, for complete claim processing instructions.
All dealers will receive a copy of this dealer notification letter by mail. Two additional copies will be sent through the DCMMS. This notification can be viewed on DealerCONNECT by selecting "Global Recall System" on the Service tab, then clicking on the description of this notification.
Owner Notification and Service Scheduling
All involved vehicle owners known to DaimlerChrysler are being notified of the service requirement by mail. They are requested to schedule appointments for this service with their dealers. A generic copy of the owner letter is included.
Enclosed with each owner letter is an Owner Notification postcard to allow owners to update our records if applicable.
Vehicle lists, Global Recall System, VIP and Dealer Follow UP
All involved vehicles have been entered into the DealerCONNECT Global Recall System (GRS) and Vehicle Information Plus (VIP) for dealer inquiry as needed.
GRS provides involved dealers with an updated VIN list of their incomplete vehicles. The owner's name, address and phone number are listed if known. Completed vehicles are removed from GRS within several days of repair claim submission.
To use this system, click on the "Service" tab and then click on "Global Recall System." Your dealer's VIN list for each recall displayed can be sorted by: those vehicles that were unsold at recall launch, those with a phone number, city, zip code, or VIN sequence.
Dealers should perform this repair on all unsold vehicles before retail delivery.
Dealers should also use the VIN list to follow up with all owners to schedule appointments for this repair.
VIN lists may contain confidential, restricted owner name and address information that was obtained from the Department of Motor Vehicles of various states. Use of this information is permitted for this notification only and is strictly prohibited from all other use.
If you have any questions or need assistance in completing this action, please contact your Service and Parts District Manager.
Customer Services Field Operations
There is no apparent difference between the two Revisions on the 2005-06 OPDA. Rev-B and Rev-E both fail.
MAJOR UPDATE! 4/17/12: The upper bushing is porous which allows the factory grease to liquify under heat and seep through the bushing into the upper shaft! It was previously though the upper bushing has no means of lubrication. Instead of editting different points and changing the content, please review the below section understanding the upper bushing recieves some type of lubrication at warm temperatures.
UPDATE 4/27/11: Added new pics with the old style OPDA upper bushing removed. There is no way for the factory grease to reach the upper shaft. Thanks tkki for the pics.
UPDATE 2/4/11: Added new pics of the old style OPDA and the oil delivery system. Thanks tkki for the pics.
There are two main differences between the two OPDA’s. The first is in the bottom section. From the outside they look identical. They share the same gear design, same oil pump drive slot, same housing machining, and same length. They share the same lower bushing.
There is an internal difference in the shaft however.
The upper section is completely changed. This is the area that is believed to be the major area of concern. With the old OPDA, there is a seal at the top of the housing.
With the 05-06 OPDA the seal is at the bottom the bushing. With the old style OPDA, oil was able to reach the upper bushing and provide lubrication. With the 05-06 OPDA, the seal prevents oil from reaching the upper bushing.
The factory grease for the upper bushing has no way to reach between the upper bushing and the shaft.
The lack of lubrication for the upper bushing generates heat and causes the shaft to seize. Here is a shaft with approximately 50K.
The bottom bushing gets some lubrication. It is debatable whether it gets enough.
Here are a few new images for tkki showing the difference in how the oil is delivered to the OPDA. The old 2004 OPDA does not have the oil channels that the 2005-06 model has to deliver oil into the housing. Instead it has a flat spot on the outside of the housing that allows oil to travel up and into an orifice on the side of the OPDA housing.
I'd like to give a lot of thanks to Jeepforum member tufmar for taking these images. They were instrumental in helping us understand what was going on. A picture is worth a thousand words.
Somehow the factory grease should find a way into the inside of the upper bushing. It was reported that there is a path between the seal and bottom on the bushing. The running theory is the grease liquefies when hot and migrates down the reservoir and into the gap between the bushing and the seal. The problem being there is no gap. There is no way for the grease to get to the inside of the bushing and on to the shaft. There have been reports that some OPDA's have a passage. This may explain why not everyone has this problem. Why some have a gap and others don't is a big issue. The bushing is pressed into the housing. Without a channel cut into the housing there is no way there is a passage unless there is a defect in the cast or some other abnormality we haven't thought of yet.
UPDATE 5/23/11 Dodge-wholesale.com has updated the OPDA. Price Drop. Price $120.75 (gasket not included +1.90)
UPDATE 4/5/11: Dodge-wholesale.com has updated the OPDA. Chrysler Price Gouging. Price $253.12
UPDATE 1/27/11: Dodge-wholesale.com has updated the OPDA to include the gasket with the OPDA. Price $99.72
(As of Nov.2010)
You should be able to find these parts are your local dealer. They will be around $180 and they may have limited stock. Several members of the forum including myself have had success with online distributors.
OPDA part number: 53010624AC $97.85
Gasket part number: J3181288 $1.87
Total including freight was $112.67
They are Jerry Ulm Dodge, Chrysler, Jeep
2968 N. Dale Mabry, Tampa, FL 33607
(813) 872-6645 dodge-wholesale.com
UPDATE 4/11/12: TDC Alignment video included below. Thanks to Bigbob.
UPDATE 1/23/11: Sharpie method video included below.
Included below are removal instructions from ElJaynocibuR followed by similar instructions from me. The section will be updated shortly with additions concerning including the alignment pin and turning the crankcase.
Originally Posted by ElJaynocibuR
Well here are a few pics. I hope they help.
Here is the camshaft synchronizer (distributor looking thing): Unplug the camshaft position sensor that is mounted on it. Remove the black plastic cover (T25 torx).
Next mark the rotor and the inside of the housing, and the outside edge of the housing and the engine block. Remember to MARK THEM CAREFULLY and DO NOT TURN THE ENGINE OVER AFTER IT'S BEEN REMOVED. (My markings aren't that great, try and be more precise than I was.)
Once you've made the marks, you're ready to remove the hold down bolt (1/2" wrench).
You can now lift the assembly out and check the oil pump drive gear at the bottom. Check for irregular wear on it. If it is wearing funny you can be sure the gear on your camshaft is wearing prematurely too. Take a flashlight and look down in the hole and you should be able to see it.
To reinstall just reverse the process. It may take a couple of stabs of the assembly to get the marks all lined back up, but it's not that hard. Look down in the hole to see the orientation of the oil pump drive you may have to turn it a little to make them line up. Once I had it set in I found it easier to reinstall the hold down bolt loosely to make the final adjustments, then I snugged it down, plugged the CPS back in, and put the cap back on. Hope this helps, if you have any questions feel free to pm me.
1. Mark the engine next to the OPDA. A little mark with a sharpie is fine.
2. Mark the housing of the OPDA. This will make sure the housing goes back correctly. You can turn the housing and that will screw up the timing so it's important to mark it.
3. Mark the sensor wheel. This is connected to the shaft and gear that is wearing.
Here is the important part, the gear from the OPDA meshes with the camshaft gear inside the engine. As long as you do not run the engine (turn it over), the camshaft will not turn. The OPDA gear will be forced to go back exactly the way it came out. Under no circumstances do you ever run the engine with the OPDA out. When you put the OPDA back it will be way off or right on the money. The gear mesh is not that fine. Think of a clock face, If your marks are at 2 the OPDA will reinstall at 12, 2, or 4. There is no 1:55 or 2:05. It will be right or wrong, there isn't a close.
This pic will help make it clear. (page 3 post 40)
4. Once the OPDA is out you can spin it to check for the shaft sticking. It should be smooth and not bind even a little. It shouldn't be loose, but smooth.
5. Check the gear for wear and check to see the oil contact. If you can get a look at the camshaft gear, try to take a pic. Odds are there will be a little shine on the camshaft gear edges. The area of concern is where the gear teeth meet. Chanced are everything is fine. If the OPDA is binding, order a new one.
6. You'll notice at the bottom of the OPDA is a slotted shaft. This will fit into the oil pump. If you happen to move the oil pump (twist it as you are removing the OPDA) the OPDA will not seat back properly. The marks will be off. If this happens (I've taken mine off 4 times, it happened once), take a flat head screw driver and turn the oil pump so the slot will fit so the marks match. If you run into trouble do not say "eh close enough", the marks need to match. You'll know if the oil pump needs to be turned if the marks don't line up with the OPDA fully inserted.
Here is a good pic of the camshaft gear and the oil pump slot. (Page 8 post 115)
On a 1-10 (10 hard) this is a 3, only because the bolt is hard to get to.
If you tear the gasket, you can get another at the dealer or just add a little RTV. I didn't tear mine after removing it twice. You can run it without the gasket if you need to replace it.
Here is a new OPDA with gear and slotted shaft end.
Oil Pump Drive and CMP Sensor
4.0L CMP Location
The Camshaft Position Sensor (CMP) on the 4.0L 6-cylinder engine (2) is bolted to the side of the oil pump drive shaft housing assembly (5).
NOTE: Do not attempt to rotate the oil pump drive assembly to modify ignition timing.
Two different procedures are used for removal and installation. The first procedure will detail removal and installation of the sensor only. The second procedure will detail removal and installation of the sensor and oil pump drive shaft assembly. The second procedure is to be used if the engine has been disassembled.
If the CMP and oil pump drive are to be removed and installed, do not allow engine crankshaft or camshaft to rotate. CMP sensor relationship will be lost.
4.0L CMP Location
Remove two plastic cover screws (7) and remove plastic cover (6).
4.0L CMP Removal/Installation
Note and mark rotational position of target wheel (4) in relationship to housing (5).
Disconnect CMP electrical jumper harness (3) at engine wiring harness.
Before proceeding to next step, mark and note rotational position of oil pump drive housing (5) in relationship to engine block. After installation, the CMP sensor should face the 4 o'clock position as viewed from right side of engine.
Remove hold-down bolt (4) and clamp.
Pull assembly from engine.
Remove and discard old oil pump drive-to-engine block gasket.
Clean oil pump drive mounting hole area of engine block.
Install new oil pump drive-to-engine block gasket.
4.0L CMP Factory Alignment Pin
If installing a new oil pump drive assembly, it is supplied with a temporary alignment pin (2) to prevent the target wheel from rotating. Do not remove this pin until oil pump drive assembly (1) has been installed.
4.0L CMP Target Wheel Alignment
If installing/returning a used oil pump drive assembly back to the engine, temporarily install a small screwdriver (1) or similar tool through target wheel access hole (2) and then through mating hole in housing (3).
Install oil pump drive into engine while aligning into slot on oil pump. Rotate oil pump drive housing back to its original 4 o'clock position as viewed from right side of engine. Install hold-down clamp and bolt. Tighten bolt.
If engine crankshaft or camshaft has been rotated, such as during engine tear-down, CMP sensor relationship must be reestablished.
Remove ignition coil rail assembly. Refer to Ignition Coil Removal/Installation.
Remove cylinder number 1 spark plug.
Hold a finger over the open spark plug hole. Rotate engine at vibration dampener bolt until compression (pressure) is felt.
Align Timing Marks - 4.0L Engine
Slowly continue to rotate engine. Do this until timing index mark (1) on vibration damper pulley aligns with top dead center (TDC) mark (0 degree ) on timing degree scale. Always rotate engine in direction of normal rotation. Do not rotate engine backward to align timing marks.
Install oil pump drive into engine while aligning into slot on oil pump. If pump drive will not drop down flush to engine block, the oil pump slot is not aligned. Remove oil pump drive and align slot in oil pump to shaft at bottom of drive. Install into engine. Rotate oil pump drive housing back to its original 4 o'clock position as viewed from right side of engine. Install hold-down clamp and bolt.
Remove small screwdriver, or, factory alignment pin from housing and install plastic cover (two screws).
Install CMP sensor to oil pump drive.
Install sensor mounting bolt and tighten to 2 N.m (15 in. lbs.) torque.
Connect CMP electrical connector to engine wiring harness.
If removed, install spark plug and ignition coil rail.
Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below steering column.
Gain access to "CAM/CRANK RELEARN" screen on DRB scan tool.
With all the above said, adjusting to TDC is an extra step that affords no extra benefit. Below is a pic of my target wheel after removing my OPDA for an inspection. I mark it twice. Once at the sensor itself and another directly opposite. The wheel needs to return to this location. As you pull the unit out the wheel will turn because of the helical gear mesh. I mark where the match mark on the wheel (YELLOW) stops and label it with an S (BLUE). This is where the orientation of the wheel needs to be when reinserting it. As the OPDA is inserted the wheel will turn to the match mark on the sensor (RED).
Here is a youtube video to show you the sharpie method. It was pretty cold out so I rushed somethings. It hopefully will give you a real good understanding of what to do and how to handle the oil pump not lining up.
Here is a youtube video showing how to clock the OPDA to use the alignment pin. This will help prevent issues with installing a new unit and offers additional protection from rubbing off sharpie marks. This method may still require an adjust to the oil pump if it gets turned. Also be aware there have been instances of codes even with TDC. I would recommend using the alignment pin instead of a screwdriver or allen wrench. There is much less play with the alignment pin that will help reduce errors.
Section 7: Modification
UPDATE 12/10/11: Using the same FogMod info below, my OPDA has been adapted to use the Oil Cup linked in the Alternate Design Section below. Simply, it eliminates any guessing with how much grease and how often. It has a slightly hire up front cost, but ultimately you save since you eliminate the need for dedicated grease.
UPDATE 1/23/11: Below is the "FOGMod" modification. At the time of this thread it was the only modification done.
Now to the FOGMod.
Pic heavy. I'll make a comment above the images. Final hindsight comments below.
8mmx1.25 Bottom Thread Tap
1/4-28 Start Thread Tap
7/64 drill bit (pilot hole)
13/64 drill bit (tap hole)
8mmx1.25 Grub/set screw 1/2 long or equivalent
1/4-28 grease fitting
Machine screw to remove Cap
3/16 Punch to remove Gear
I had a vice and a center punch and some other niceties. You can do it without them.
The modification below begins with the OPDA apart. To do this you must punch out the roll pin and remove the gear. Once the gear is off, pull the shaft out.
Here is a pic of the groove added for the lower bushing. In recent discussions this may not be necessary. I feel better with it and it was free. If you have to pay a shop to do it, weigh the cost/reward. The groove is 360 degrees 1 1/8 long.
First I removed the factory plug. I took a punch and added a hole. I inserted a machine screw and pulled out the screw with some vice grips. The cap is not hard to remove.
Once the plug is removed you'll see the factory hole steps down from the approx. 8mm opening to a 7mm-1/4inch opening. You can also see the "peanut butter" factory grease (yellow pic).
Once the cap was removed I threaded the larger 8mm opening for a grub screw. I loaded the threader with grease to capture as much metal as possible. Since the opening gets smaller I used a bottom tap.
From there I went to the jeep to see the best location for the new grease fitting. I decided a little left of the LDI label between the oil filter and the motor mount.
I started with a 7/64 pilot hole and went to a 13/64 tap hole for a 1/4-28 fitting.
Without drilling the bushing I install the grub screw in the factory hole and the grease fitting in the new hole to see if I could determine where the grease would normally come out. NO SUCCESS. If there is a way I couldn't find it. I tried high pressure air with no success either.
Finally I drilled the bushing using the same 7/64 bit I used for the pilot hole. Drilling the bushing was easy. I added grease to the drill bit to catch shavings (this in not the actual size drill bit for the bushing. It is meant to show the greased bit and metal shavings). I drilled the bushing through the factory hole.
Here is the final project. The white is thread sealant. The grub screw has red hydraulic locktite.
Here is a cut-away with a top view. The green line is where the zerk is located. The actual position will vary. You can put the zerk anywhere that is comfortable for you.
The green arrow is where the grease will enter the reservoir. The yellow area is the grease reservoir that surrounds the outside of the bushing. You will drill the hole in the bushing through the factory hole. The red arrow shows where the grease will enter the bushing and contact the shaft.
Here is the final install. I changed from the long shank traditional zerk to a flush mount zerk commonly found on drive shafts. Personal preference. I've install two others with the long shank with no issue. I made the mods on mine and the placement made it tight for the grease gun. With the other modded units I adjusted placement a little lower and there are no issues.
1. I should have installed the grease fitting a little lower to help the grease gun fit on the fitting without interfering with the sensor head. It fits, buts it's close.
2. I may change the fitting to a recessed fitting and use a needle. I don't know if I like the extended fitting.
3. Remember the housing is aluminum so be extremely careful not to over-tighten the fitting or screw. The threads can easily stripe. Tight enough is all you need. This is why I think I'll go with a recessed zerk and needle.
4. When drilling through the housing, you will feel the drill bit bottom out. Don't worry about drilling too far. I was concerned when drilling the new grease fitting hole that I would accidentally drill through the bushing. Not an issue at all.
5. When cleaning the metal shavings out make sure to cover the sensor. It is magnetic and I have a bunch of shavings to clean off.
UPDATE 12/22/11: Included Shell Rotella T and T6 to the recommended oil selections. Links listed below.
Update 6/8/11: More of a summary of recommended oils. In no particular order:
- Mobil 1 Turbo Diesel Truck 5w40
- Valvoline VR1 Conventional Oil 10w30
- ZDDPlus Additive with/ Personal Oil Preference
Update 1/30/11: Added info on Valvoline VR1 Racing Oil.
Full Disclosure: I'm no oil or grease guy. I trust the other contributors hunting down information. Jeepforum member TheFOG is our main resource.
Oil: Specifically, what engine oil should I use to help prevent this problem? This will likely be a touchy subject considering the lot of threads asking "what oil is best" along with the lot of different answers. This information is based on a ratio of part opinion and part fact. Ultimately you will have to decide on the oil of choice. The information provided here is not meant to sway your choice, but to offer some insight on what can help.
*Also, it probably goes without saying, but I'll say it nonetheless. The Jeep engine holds 6 quarts. A lot of oil specials only include 5 quarts. The OPDA requires oil to defy gravity and migrate through a series of bends and channels. A quart low will make this even more difficult.
The most common EP additive in automotive engine oils is zinc dialkyldithio-phosphate (ZDDP), a family of coordination compounds of zinc and dithiophosphoric acid which, in longer chain, molecular derivatives, easily dissolve in engine oils. Known more commonly as "zinc dithiophosphate" (ZDP), "zinc phosphate" or, quite incorrectly, just "zinc", this compound was initially added to oil in the 1940s as an anti-corrosive/antioxidant. Later it was discovered to be an excellent extreme pressure lubricant.
When subjected to heat present at the lobe/lifter interface, ZDDP decomposes into alcohol, zinc, sulfur and phosphorous. The alcohol
evaporates and the zinc mostly washes away, leaving sulfur and phosphorous to combine with iron molecules on the surface of the cam lobe to make iron sulfide and iron phosphate, the two compounds which perform EP lubrication.
"The 'dithio' in 'zinc dithiophosphate' means for every phosphorous there are two sulfur molecules," Red Line Synthetic Oil Corporation's Vice President and top petro-chemical engineer, Roy Howell, told the Corvette Action Center.
Sulfur is probably more important than zinc and phosphorous. The cam and lifter wear surfaces are rich in iron and sulfur with a lesser amount of phosphorous. The ZDP decomposes into a soft, thin film of iron sulfide and iron phosphate which prevents iron adhesion, or welding. The zinc doesn't do much. If you look at photomicrographs of cams and lifters, there's hardly any zinc coating, but there's a lot of iron sulfide coating and some iron phosphate coating.
With this process, you trade adhesive wear for chemical wear. If you didn't have these soft films, which prevent iron from touching iron if you didn't have something in the middle, then you'd get adhesive wear-welding and that iron-to-iron weld would pull 'chunks' out of the lobe and follower.
What makes zinc dialkyldithiophosphate unique is its precise thermal decomposition temperature which can be manipulated by changing the composition of the organic alkyl group attached to the phosphorous.
If it decomposes at too low a temperature, chemical wear would occur where it is not needed but, if it occurred at a higher temperature, then some adhesion or welding, would already be taking place.
There are a lot of different sulfur compounds Howell continued, but this one has 'precision-controlled' decomposition. In many of the
others, the sulfur and the phosphorous are much more loosely bonded. There's a bigger 'range'. It might partially decompose at a lower temperature and finish at a higher temperature or, maybe, decompose only at a higher temperature, however, with ZDP-boom!-, like at 400°F, it starts to thermally decompose then react with the surface of the lobe and lifter to form those almost monomolecular soft films. As the lobe rubs against the follower, that film will get rubbed off and in the next revolution, the same thing happens again."
ZDP is slowly depleted by decomposition and evaporation, so eventually EP lubrication becomes inadequate. This is one reason oils need to be changed periodically.
While some petrochemical engineers consider sulfur of primary importance and some consumers misunderstand zinc content as benchmarking EP additives in oil; in reality, it is the phosphorous component about which the oil industry is most concerned.
As far as the oil goes yes you NEED to run a ACEA rated oil like mobile 5W-40 or 0W-40 if its Eskimo cold. Yes plenty of people will say they have ran brand X of regular oil with no problems and that maybe true. But the problem is the oils are being changed all the time so the brand X oil you bough 5 years ago isn't the same as the brand X today.
As far as synthetic goes IMHO there is no point in running in your diffs, transmission, transfer case ETC. But when it comes to crankcase oil yes there is a big difference. There is a reason why the Europeans came up with the ACEA rating system and why you won't find non-synthetic oils that are ACEA rated.
Of the oils I've tested with different gears the Mobile 5W-40 "turbo diesel truck" oil has shown the best results. As far as the diesel label its also approved SM and ACEA for gasoline engines. If you still can't get over the diesel label you can also run 0W-40 "European formula"
I know some of those out there are stomping their feet with their owners manual in one hand saying Chrysler doesn't spec a 40 weight oil its too heavy. Well first off consider the same idiot that is telling you not to run a heavier oil is the same idiot that designed this crap-tastic CPS unit.
But from the scientific side the 4.0 used to be speced at a 40 weight oil before the CAFE fuel standards became an issue. Also realize that the 4.0 runs hotter than most engines and doesn't have a oil cooler so it does benefit from the thicker oil.
These pictures are of lifters out of a 04 LJ with ONLY 27,000 miles on it. After reading around on ROF this isn't an isolated incident. There have been several other TJ owners with low milage that had engine failure as a result of worn lifters.
I've noticed most of these failures are of the later TJs and with low miles. After thinking of a bit I came up with a theory that gets back to ZDDP. Most engines don't just "wear in" or "break in" for the first couple thousand miles. Yes there is allot of "break in" during the first couple thousand but with engines like ours it continues for 10-20K miles IMHO.
My theory is the earlier 4.0s were broken in their first 10-20k miles running SL rated high ZDDP oils. Once the engines were pasted that 20K mark they have finished "seating" or "wearing" in the most critical parts in the engine.
Now with the later models (04-06) they went into production after the EPA mandated the lowering of the ZDDP. Because of this those first 10-20K critical miles were with a low ZDDP oil which set up the engine for problems down the road.
Some of the guys here can argue all they want about the lack of ZDDP not causing any problems and not being the source of the gear failures. But I grew up around Jeeps and the 4.0 and never saw one much less several that were totally stock eat a lifter especially at such low mileage.
Originally Posted by Xlr8n
Just an FWIW on best oils for the 4.0:
After realizing the Mobil 1 High Milage Formula now contains reduced levels of Phosphorus and Zinc (900 ppm and 1000 ppm respectively) which are only mariginally better than any other SM oil, I had turned to Mobil 1 Turbo Diesel Truck 5W-40 like many others here, but I was still not completely satisfied with the TDT formula due to the Phosphorus and Zinc levels (1100 ppm and 1200 ppm) still being below those of the older SL oils that the 4.0 seems to need.
Realizing the oil makers are constantly changing formulations, I did a bit more research over the past couple days and came up with looks to be an even better choice:
Valvoline Racing VR-1 10w30 Conventional formula.
I had previously discounted any "racing" oils as most are not intended for street use, but Valvoline advertises this as an oil suitable for both track use or passenger car use with Phosphorus and Zinc levels (1400 ppm and 1300 ppm respectively) at or above those in the original SL oils the 4.0 was designed to run on.
The 2 major benefits of the VR-1 conventional over the M1 Turbo Diesel Truck oil are:
1) It's the exact 10W-30 viscosity grade recommended for the 4.0
2) It has the higher levels of ZDDP.
If the fact that this is a 'racing oil' bothers you, don't let it. This is a separate series of oils than the true Valvoline racing oils which are actually labeled "not for street use".
Keep in mind, if the VR-1 conventional oil was advertised as a regular oil, Valvoline wouldn't be able to offer the higher ZDDP additives due to the current government restrictions. They are using a loophole by calling it a 'Race' oil. The VR-1 oil is in fact stamped with the 'API SL' designation, the same designation as the oils that the Jeep 4.0 were filled with when they left the factory. The true race oils usually have no designations.
The dino formula VR-1 goes for about $5 a quart.
I'll likely be changing to the conventional VR-1.
As a side note, it's interesting that just a couple years ago, none of the oil companys would mention anything about the Phosphorus/Zinc issue, but now that premature engine wear problems continue to be reported, satisfactory oils are becoming available.
Are there any other Oils that have a high ZDDP property? Yes, Shell Rotella T and T6. Blackstone lab reports for each linked below. Thanks to Rubicon17 for the help.
Grease: Grease will be required to service the upper bushing lubrication.
FOG has recommended several greases for servicing the upper bushing. Of these greases, Shell Aeroshell 33MS is the grease of choice. Below is a link to the specs. FOG has reported that an OPDA using this grease was disassembled after 20K miles with no wear/heat damage to the upper bushing.
AeroShell Grease 33MS is an extreme pressure (EP) grease based on the proven lithium complex technology of AeroShell Grease 33, and is fortified with 5% Molybdenum Disulphide. The benefits of Grease 33MS include: Improved anti-wear and corrosion resistance over AeroShell Grease 17; It is fully compatible with AeroShell Grease 33, so reduces the risks and problems associated with misapplication; Load carrying and EP properties equal to that of the well established AeroShell Grease 17; Fully approved to MIL-G-21164D. It possesses enhanced anti-wear and anti-corrosion properties and is particularly suitable for lubricating heavily loaded sliding steel surfaces, such as, for example, bogie pivot pins on aircraft landing gear-assemblies. AeroShell Grease 33MS is a direct alternative to AeroShell Grease 17, but when changing from (clay-based) ASG 17 to (Li-complex based) ASG 33MS, the normal rules on grease changing should be applied.
Brand Name: Aeroshell
NLGI Grade: 2
Application: see below
Oil Viscosity cSt at 40°C: (Kinematic) unavailable
Oil Viscosity cSt at 100°C: (Kinematic) 3
Dropping Point °C: 500+
Max Op Temp °C: 149
Min Op Temp °C: -73
Worked Penetration: 295
Timken OK Load lb: unavailable
Extreme Pressure: yes
Food Grade (NSF H1): no
Section 9: Questions and Answers
UPDATE 2/21/12: Included OPDA replacement.
UPDATE 11/27/11: Included roll pin question.
UPDATE 9/12/11: Included link to crown gear installation info provided by Rubi4MyMrs post 1867.
UPDATE 7/12/11: Changed the Format of the Q&A to hopefully be a little clearer. Some questions have a link to the answer (and typically the area of the thread discussing the subject). Some questions will have the answer directly below, and some will have both. The goal is to make it easy to find your question and navigate to the answer.
All that said, I have seen several OPDA's that are not drilled perfect center (perhaps by design). This may mean that even with the 2004 gear you will have to re-drill. It is a gamble. I would recommend that anyone who is uncomfortable drilling a new hole through the OPDA shaft, to get the 2004 OPDA and try to make it work. Barring anything else a complete replacement or a trip to a local machine shop are the other options.
5. Why can't I just install a 2004 CPS?
The new-style cam position sensor needed for the 2005-2006 ECU won't fit in the older unit. The older unit's cam position sensor is incompatible with the 2005-2006 ECU.
6. Can I reuse the roll pin holding the gear in place?
Yes. Secure the OPDA in a vise or similar so the gear is stable and clear so the roll pin can be pushed out. Use a 3/16 punch. The roll pin is tight so tapping will not work. Forceful steady blows should dislodge it. WARNING! Remember the gear is drilled through the shaft offset so the gear can only go on one way. Before attempting to reinstall the gear look through the hole to ensure clearance. Try putting the gear on the opposite way to see what the offset will look like.
3. What Oil should I use?
A detailed explaination of ZDDP an oil additive designed to reduce wear is described above in the Oils and Greases section. As of 12/2011 Mobil 1 5w40 Turbo Diesel Truck has been shown to be effective. High ZDDP oils included:
- Mobil 1 5w40 Turbo Diesel Truck
- Valvoline VR-1 10w30 (conventional)
- Shell Rotella 5w40 T and T6
The quick and dirty answer is match the sharpie marks. You align the target wheel of the new unit to match the old and make a mark. Some prefer the alignment pin. There is some extra effort, however you may prefer the technical approach. TDC is described above in the Removal Section. Please remember to remove the alignment pin if you decide on this approach.
UPDATE 11/27/11: Post restricts images to 20 so follow this link (page 152 post 2271) to the update after 9500 miles.
Update 4/18/11: Added my update after 2000 miles. See below.
Update 2/11/11: Added tkki1230 update after 6000 miles. See below.
We're still pretty new to this whole thing. Just a quick history relating to these photos.
When I first had the problem I was still under the 7/70 warranty. I wanted to have it documented that I had this problem so I went to the dealer. In hindsight I regret it. Anyway they replaced the OPDA with a REV-E (originally had a REV-B). I changed the oil to Mobil 1 5w30 High Mileage. I ran it for about 5000 miles. In the meantime I ordered a new OPDA and preformed the mod on the new unit. At the time I have Mobilith 220 Synthetic Grease handy so I used that instead of the Aeroshell 33MS. Below are the results.
This image compares a dirty modded unit and a clean stock unit. Both with relatively low miles. The damage to the bottom shaft is nearly identical. I show no evidence that the oil groove has any significant value. That said we are talking 500 and 5000 miles respectively so I wouldn't put very much stock on these initial results. What you take from this is that the scoring happens almost immediately (500 miles).
This image shows a wiped down shaft with the modded OPDA. This image shows discoloration and some scoring. You can also see where excess grease slung from the top of the OPDA. I was disappointed with the results, however the grease I elected to put in was a much MUCH thicker grease. To put it in perspective the Mobilith 220 has an oil viscosity of 220 at 40°C while the Aeroshell 33MS is 14.2 at 40°C. At this point I can rule out Mobilith 220 as a viable grease.
I've replaced the modded OPDA and purged the Mobilith 220 with Aeroshell 33MS. I'll pull it again after 5000 miles.
Originally Posted by tkki1230
I just pulled the OPDA replacement unit out of my jeep to check the wear. This unit has the FOGMOD. Here's a pic of the shaft after 6000 miles.
The upper bushing area on the shaft where the grease is looks really good [NOTE: the upper bushing was greased with Aeroshell 33MS]. Just a little discolored, but no wear or scoring. Nice and smooth! The lower bushing was scored about a thousandth. That seemed kind of excessive for just 6000 miles. I'm going to send this to the machine shop to get fixed.
The upper bushing in the unit was perfect. So far so good with the FOGMOD, as far as my unit goes.
The lower bushing wasn't too bad, but there was a little wear, about half a thousandth.
Originally Posted by willydigger
I pulled my OPDA after changing the oil. I'll post some pics up later. The bottom shaft looked good. It had oil, but I have a groove. The scoring didn't advance beyond the pic at 500 miles. The upper bushing was okay. The Aeroshell is much better than the Mobil 220. It didn't clean up as well as I'd hoped. The gear teeth looked a bit worse so I think it may be the normal wear.
Here is the gear. The wear spots are small, but larger than before.
Here is the bottom shaft. There is scoring, but it's not bad.
Here is the upper. It is dark, but the grease is wet.
Notice the really dark spot below. This did not wipe away clean. My batteries died on the camera so I didn't get a shot. The entire upper wiped away clean except for the dark spot.
It didn't feel weird. The bushings looked good with minor wear. I would expect the wear on metal to metal contact. Overall the OPDA was in good shape. The mileage is 69K, 2000 more than the first pics. Below are the before images for easy comparison.
Actually now that I look at the before pics, the gear teeth look the same. The shaft cleaned up nice and shiny like the before pics. I'm disappointed because I wanted to Aeroshell to wipe away with no marks. While it was much better than the 220, it wasn't perfect. Now my experiment is to put a little less grease in. I was pumping it until it got hard to pump. Maybe it was too much grease.
UPDATE 4/13/12: Added explanation video to oil bath design.
UPDATE 2/25/12: Added Bigbob Flow Through Design.
UPDATE 12/12/11: Added efm-7 oil bath design.
UPDATE 12/10/11: Added like to oil cup design discussion and updated pics. I have adapted my FogMod to the oil cup design.
UPDATE 7/17/11: Added mod to help introduce oil into the lower bushing section of the OPDA, inspired by the 2004 CPS.
UPDATE 7/14/11: Added link to preliminary results from Rubi4MyMrs oil cup modification.
UPDATE 4/27/11: I've decided to set aside this post as a alternate ideas section. There seem to be a few that have grown as the discussion progresses. While the FogMOD is still in the infancy period there have been some other ideas that may be of interest to some and in an effort to reduce searching through hundreds of posts I'd link things here.
Excellent post...I would be interested to know why there are no aftermarket replacements to fix the problem....but in their absense ill probably install the grease zerk when I buy a 2006 in a few months
Its a patented part and cannot be made aftermarket. I've spoken to several vendors about making one and they all said they would like to but legally can't.
In memory of Samantha Sue 1998 to Dec-16-10 at 2:15PM. She may have had 4 legs and a tail but she was the best friend I ever had and helped me through some really tough times. I hope to see her again one day.