I've started a couple of threads regarding a problem I've been having with my 2008 JGC CRD Overland with the Quarda-Drive II system.
The first thread was about the MOPAR LSD additive. For reference, my mechanic didn't add the additive when the fluid was changed. I drove for 5000km (~3000 miles) before I started to notice the symptoms. I had replaced the transmission, transfer case and e-LSD (with MOPAR Friction modifier) fluids using the recommended Amsoil products - not MOPAR. You can see the details in the thread.
The second was about the specific symptoms I've been experiencing. Most of the responses I've gotten suggest that it is a CV half-shaft.
Today I went to see my mechanic friend and he took the Jeep out for a spin to see if he could determine the problem. When in drive and with the wheels turned either left or right I would get a "clunk" or "pop" feeling in the steering wheel that you could feel in the floor. It seemed to be even more prominent when going in reverse with the wheels turned to the left. You could feel the Jeep shudder a little. I originally thought that it was only under load but we picked up some speed, put the Jeep in neutral and then let it coast while in a turn. Near the point that the Jeep would come nearly to a stop there would be a "clunk" and the Jeep would stop. When it got more evident it was more of a grinding sound. It doesn't "pop" at a specific radius of the wheel turn and it isn't a consistent rhythmic pop.
From what my friend tells me he thinks that it's driveline windup/binding. He believes that it may in the front e-LSD. He's not certain if there's a second LSD other than the rear e-LSD and neither am I. Perhaps in the transfer case?
Does this sound like something anyone is familiar with?
4x4 systems are new to me. Any advice would be very helpful.
I had a front drive shaft outer CV start to bind (left hand side if I recall correctly), only noticeable when turning sharply at low speed. it was only after I removed the front shaft that the problem was obvious.
Fitted the new tires to my WK GR Ch to try and cure locking center diff problem and guess what - absolutely no change! Centre diff locked with in 400m of me driving out of my yard and again 2 more times in the 2 mile round trip.
I am beginning to think this is a fairly common issue and all the BS about fluids and friction modifiers is just that - BS! Jeep are again trying to cover up for the fact that the center diff locks randomly and adding a friction modifier just allows the plates to slip when in fact they should be mechanically disengaged.
Ever wondered why the 3.0L CRD engine only gets 26 miles per imp gallon in this vehicle when the same engine gets 40mpg (highway) in the Mercedes MIL (same shape weight and tires).
New Actuator arrives later this week. Fingers crossed!
To answer your (rhetorical) question, the ML320 CDI has a 7-speed automatic transmission, if I'm not mistaken. From what I can recall reading (a long time ago...) Jeep opted to go with the 5-speed (Chrysler: W5A580/NAG1 - Mercedes: 722.6/5G-Tronic) transmission to mate to the OM642 due to its higher torque capacity than the 7-speed, greater towing capability and off-road capability. I don't remember which performance Mercedes vehicle it was, but I recall that when choosing between the 5-speed and the 7-speed options, MB opted to use the 5-speed due to its higher torque capacity. Regardless, I think the additional 2 gears is the reason why the MB gets better fuel economy. Given that my CRD revs at around 2500-3000RPM at cruising highway speed (120-130kph), a lower gear would make sense.
I've never seen an OM642 rated that high. Do you have any evidence of this? I doubt the 7 speed would be adding 15mpg's since all i ever see listed is around mid 20's for MPG with the occasional 30mpg on the 2wd models but even thats a long stretch to get to 40 mpg's.
Enjoying the sidetrack, I found this site that says the 2007 ML 320 diesel gets 24mpg highway, which would remove the need for a conspiracy (in any case, I had a diesel that could go from 20mpg to 2mpg with a button push, so I could have believed it). I'm not sure what to make of the mystery, except maybe it was a mixture of recalling miles per gallon and kilometers per gal (if I have it right, that would be 38 kilometers per gal). https://www.fueleconomy.gov/feg/noframes/23914.shtml
I'm very curious what's causing his lockup. I'm pretty sure I saw a youtube video of a similar problem but it was being referred to as chain slippage for some reason.
The point of LSD additive is to allow the clutches to slip MORE. With binding clutches, I would consider another service with the specified fluids, then take it out and do some figure 8's to really stir the fluid up well and work it into the clutches. There are clutches in the front and rear diffs as well as the transfercase, though the nv245 fluid does not require any type of additional additive.
Gents,
Sorry if I am misleading you on the comparative mileage with the same engine in the Merc ML but I had the pleasure of driving one with the 3.0 L V6 turbo diesel (maybe a bit newer 2010 ish and a UK new vehicle) to Glasgow recently and while cruising at 60 to 70mph on a flat road the car was averaging 40mpg as per the dash readout, but we have bigger gallons than you but still quite a significant improvement over the 30 or so mpg (UK imp G) that the Jeep can achieve in its best condition. Your standard highway tests do return a bit less than what I would call average cruising economy and US models may also be sightly less efficient due to your stricter emissions regulations (I have not completely figured out why sacrificing mpg is better for the environment but I get it is to with reducing some harmful exhaust components NO's, Co and unburnt fuel etc and not just reducing the amount of fuel used).
You may be relieved to know I have fixed my problem with the binding drive train in the Jeep. Its like a new car.
I suspect this problem has been with the car for the last 2 years and the previous owner did not notice or repair it (neither did the Jeep dealer who sold it to him in late 2015) and this may account for the worn front tyres and the fact it has done so little mileage over the past 3 years - no one would want to drive it. It is only when it got so massively worse after the recall work that I was forced to get into the detail of the fault (since the dealer and Jeep would not help).
It's a bit of a Christmas miracle and the car is back from 16mpg (US gal as per DIC on dash) to 28mpg (30 ish UK mpg) on a trip so very happy and no more thumping drive shaft episodes. When I get a chance I will write it up with photos for the benefit of readers.
No so much of a conspiracy as first though just a combination of poor design, quality control and bad programming in the FDCM (maybe because of the N23/P73 recall) software causing unforeseen interactions and frankly still unexplainable interactions between the rear diff and the centre diff but I am reading up to see if I can find the link.
Does anyone know if the rear axle has sensors which can measure or calculate torque to each rear wheel? The maintenance manual mentions abs sensor disconnection when removing the diff nugget but as far as I can see it only has abs wheel speed sensors at the outer wheel bearing/hub and just a 2 wire connection to the elsd solenoid in the nugget. It is possible it makes a comparison left to right to calculate twist if speed pulses get out of sync. I only have a copy of the earlier 2005 to 2008 manual so it maybe inaccurate for my model - 2010. I did find quite a few inaccuracies and cut and pastes from earlier models.
If the elsd clutches and centre diff clutches are mechanically/hydraulically disengaged, as they are supposed to be in normal driving on a flat straight road or even in moderate corners and manoeuvring, then there is no need I can see for adding anti friction additives. These may just stop it working when you want it to bind up. The programming in the FDCM is supposed to prevent binding for maximum economy when in normal driving. Try driving a ford ranger (my other truck used for towing the competition 4x4 trialer) with the transfer case locked in high ratio on the road and see what it does to performance and fuel economy.
Also still looking to find a plot of the radial movements of the transfer case actuator and the voltage feedback limits for the various actuator positions, both pre and post N23 updates. manual was not much help and only had voltage feedback limits for AWD (0.45 to 0.55V) and 4WD low diff locked(4.19 to 4.35V), I am guessing due to age of manual these are pre N23 update.
Merry Christmas to all and I hope to post a comprehensive report in the new year.
Gents,
Sorry if I am misleading you on the comparative mileage with the same engine in the Merc ML but I had the pleasure of driving one with the 3.0 L V6 turbo diesel (maybe a bit newer 2010 ish and a UK new vehicle) to Glasgow recently and while cruising at 60 to 70mph on a flat road the car was averaging 40mpg as per the dash readout, but we have bigger gallons than you but still quite a significant improvement over the 30 or so mpg (UK imp G) that the Jeep can achieve in its best condition. Your standard highway tests do return a bit less than what I would call average cruising economy and US models may also be sightly less efficient due to your stricter emissions regulations (I have not completely figured out why sacrificing mpg is better for the environment but I get it is to with reducing some harmful exhaust components NO's, Co and unburnt fuel etc and not just reducing the amount of fuel used).
You may be relieved to know I have fixed my problem with the binding drive train in the Jeep. Its like a new car.
I suspect this problem has been with the car for the last 2 years and the previous owner did not notice or repair it (neither did the Jeep dealer who sold it to him in late 2015) and this may account for the worn front tyres and the fact it has done so little mileage over the past 3 years - no one would want to drive it. It is only when it got so massively worse after the recall work that I was forced to get into the detail of the fault (since the dealer and Jeep would not help).
It's a bit of a Christmas miracle and the car is back from 16mpg (US gal as per DIC on dash) to 28mpg (30 ish UK mpg) on a trip so very happy and no more thumping drive shaft episodes. When I get a chance I will write it up with photos for the benefit of readers.
No so much of a conspiracy as first though just a combination of poor design, quality control and bad programming in the FDCM (maybe because of the N23/P73 recall) software causing unforeseen interactions and frankly still unexplainable interactions between the rear diff and the centre diff but I am reading up to see if I can find the link.
Does anyone know if the rear axle has sensors which can measure or calculate torque to each rear wheel? The maintenance manual mentions abs sensor disconnection when removing the diff nugget but as far as I can see it only has abs wheel speed sensors at the outer wheel bearing/hub and just a 2 wire connection to the elsd solenoid in the nugget. It is possible it makes a comparison left to right to calculate twist if speed pulses get out of sync. I only have a copy of the earlier 2005 to 2008 manual so it maybe inaccurate for my model - 2010. I did find quite a few inaccuracies and cut and pastes from earlier models.
If the elsd clutches and centre diff clutches are mechanically/hydraulically disengaged, as they are supposed to be in normal driving on a flat straight road or even in moderate corners and manoeuvring, then there is no need I can see for adding anti friction additives. These may just stop it working when you want it to bind up. The programming in the FDCM is supposed to prevent binding for maximum economy when in normal driving. Try driving a ford ranger (my other truck used for towing the competition 4x4 trialer) with the transfer case locked in high ratio on the road and see what it does to performance and fuel economy.
Also still looking to find a plot of the radial movements of the transfer case actuator and the voltage feedback limits for the various actuator positions, both pre and post N23 updates. manual was not much help and only had voltage feedback limits for AWD (0.45 to 0.55V) and 4WD low diff locked(4.19 to 4.35V), I am guessing due to age of manual these are pre N23 update.
Merry Christmas to all and I hope to post a comprehensive report in the new year.
The limited slip still have pressure against the clutches without power sent to the solenoid to plug the pump bypass. Lift an axle and rotate a wheel, it will spin the other the same direction (if the rig is in neutral and allows it) because there are clutches driving the other wheel the same direction similar to a conventional LSD. Unlike a conventional LSD, the c213re and C200fe axles use a pump to apply MORE force against the clutches when more force is desired. LSD additive is still required for desired operation.
The voltages given for the transfer case are normal 5v operation. about .5v-4.5v leaving >.5v and <4.5v as diagnostic voltages. It knows there is a problem if it sees 0 or 5 volts.
The traction control uses the abs wheel speed sensors to identify a slipping or skidding wheel and take action (applying the brake, releasing the brake, control LSD's accordingly)
Thanks for all the helpful comments above. In my vehicle sensor inputs from the back axle were causing the transfer case actuator to flutter about 10deg which I think may be into the region where it locks the center diff hence the thumping driveshafts. There were no codes or other obvious mechanical problems so it has bee a bit of a head scratcher. See attached photo of the wear pattern on my actuator position sensor. When I get a proper scanner that can read inputs and out data on the fly I might be able to explain why this happened (and has been going on for years but got so bad the truck was undriveable after the recall reflash of the FDCM).
I did make a blaring error above when discussing mpg. US gallons are the same as UK it is US barrels that are smaller (40 gal vs 44 gal) so my mpg is as per the dash readout - thirsty bugger but still back to spec and lot better than before so should be grateful.
More in the New Year. Hope santa brings you all you wished for and a Happy and prosperous New Year.
I don't think the point is that your rear wheel sensors are moving the actuator. The point, I think, is that some sensors are making the computer think you're having wheel spin, so the computer is doing it's job and locking you into a true four wheel drive. There are no codes when the computer is doing it's job. You don't get a code that says your tire spun (do you? I don't actually know). It just does it's job, so unless your computer knows the sensors are lying to it, it won't throw a code.
I get the feeling you're thinking the transfer case is malfunctioning, or that your wheel sensors are directing the transfer case actuator, but from your description, it's just doing what the computer is telling it to do. It also seems the computer is being fooled by some sensor issues into thinking you're spinning. Maybe you need to be checking out why it thinks the wheels are spinning, instead of looking at the components that are reacting to the wheel spin.
I apologize for being scatter brained, but didn't you have mismatched tires for an extended period of time? If so, I'm wondering if there isn't some worn out parts from that issue that are confounding your symptoms. I'm sorry if I've conflated a couple threads.
You might need to start a new thread for yours. It seems his issue centers on his transfer case behavior, and I think you have a different transfer case. Good luck to you.
What did you do to fix the thump? Your post indicates some possible causes but not the solution. As for MPG, the UK jeeps show US MPG. The US gallon is over half a liter smaller than a real Imperial gallon.
I think I have a collapsed front drivers brake hose causing some thumping. When I jump in the Jeep in the morning and gently slip it into drive it will roll away no problem. After you use the brakes a couple times it takes effort to pull away from a stop. I get some off-coasting thumping on the highway too. It's been a tough one to figure out due to having multiple problems with the Jeep.
What did you do to fix the thump? Your post indicates some possible causes but not the solution. As for MPG, the UK jeeps show US MPG. The US gallon is over half a liter smaller than a real Imperial gallon.
I think I have a collapsed front drivers brake hose causing some thumping. When I jump in the Jeep in the morning and gently slip it into drive it will roll away no problem. After you use the brakes a couple times it takes effort to pull away from a stop. I get some off-coasting thumping on the highway too. It's been a tough one to figure out due to having multiple problems with the Jeep.
If you have a sticky brake, it will heat up much faster than the others. If it were me, I'd start out leaving the house cold, then stop a few times and get out, putting my fingers on the rim, lug nuts, then brake rotor itself (in that order, stopping when one is hot enough to burn). Check all 4 at the same time, and quickly when you get out (the temperature difference will quickly fade, so if you screw around after you stop, don't bother checking).
Calipers can stick, which is more common than a collapsed hose in my experience, but hoses do go to hell and can hold some pressure. Below is a brake hose that will hold pressure for some time after you let off the brake. You may notice the outside looks good:
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