Shudder at 1st to 2nd gear shift point - JeepForum.com
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post #1 of 16 Old 09-21-2021, 08:39 PM Thread Starter
Steve.A
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Shudder at 1st to 2nd gear shift point

I test drove a 2013 JGC Laredo with the 3.6 and 147K miles tonight and noticed a distinct shudder, or jerk at what would be the 1st to 2nd gear shift point. It felt initially like the vehicle was shifting from 1st to 2nd almost immediately after acceleration. It did this upon every start from a dead stop. I shifted manually to 1st gear from a stop and the shudder still occurred when taking off from a start, with no change in RPM and no shift to 2nd gear. The current owner was with me and said that the vehicle had this issue since he bought it and even took it to a dealer once, who said that there were no transmission issues. I believe that this is the QT1 (MP2010) transfer case. If the transfer case was a QTII, I'd suspect the clutch pack and think a fluid change may help this. But, since this is a QTI, this is a chain drive, isn't it? Is there anything in the transfer case that could be causing this, or should I look elsewhere for the issue? Otherwise, the vehicle checked out fine and ran and shifted great. I didn't have my good scanner with me, but used a basic scanner and found no issues for either generic or OEM specific, and the live data all looked good. I did a search of the forum and did find a similar issue mentioned with the QTII transfer cases, but the Laredo has a whole different TC.

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post #2 of 16 Old 09-21-2021, 10:06 PM
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You can google search for NAG, which is the Mercedes transmission used in a 2013 V6. I believe they are noted for shudder and sensitivity to oil fill level. If I recall there have been several "enhancement" flashes that lessen the shudder. The transmission is strong, but not spirited, up shifting early and down late. What you observe may in fact be normal. Some think the early shifts drops RPM to the point where the engine struggles.

If the Jeep doesn't have a select terrain knob, it is the single speed MP2010. It has a chain off the center diff (open) that drives the front drive shaft that can jump when worn. But thats not a shudder feeling, more of a pop.

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #3 of 16 Old 09-22-2021, 08:35 AM
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Usually, a low fluid level on a NAG Auto results in slipping of the first gear clutch, not 1st to 2nd gear. I would still suggest you check the fluid level even if it's just to eliminate this as a potential cause. There isn't a dipstick so you have to buy a $15 aftermarket tool. This includes a chart to show what the fluid level show be at specific temps, I seem to recall it's 65mm at 165F.
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post #4 of 16 Old 09-22-2021, 09:06 AM
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There is a fluid level check procedure indexed in the Maintenance/Repair sticky. You will need a dipstick long enough to reach the pan bottom and then you measure the level.

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #5 of 16 Old 09-23-2021, 11:08 AM Thread Starter
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ColdCase and Bilko, I really appreciate the feedback on the NAG transmission fluid level. I plan on getting the WK2 tomorrow. The price is good and other than this issue, it seems in pretty good shape. It will need a catch up on a lot of maintenance issues. The first owner was very fastidious on maintenance and I have good records up to about 90,000 miles, a couple of years ago. The second owner was a very high mileage driver and did very minimal maintenance in the almost 60,000 miles he drove it in about 3 years. Fluid/filter changes for all drivetrain components, including transmission are first on the list. Thanks again for the tips. This will be my first WK2. I've got a WK now and in the past couple of years have had numerous WJs and KKs. The WK2 has quite a few differences from what I'm used to, other than the Pentastar 3.6L that I had in another Chrysler product. I'm looking forward to more of the sage advice I received in the other forums, although I'm much more of a lurker than a poster, unless I think I can contribute.
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post #6 of 16 Old 09-23-2021, 11:29 AM
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Looks nice and clean.

The other zero-cost fix to try for the shifting problem is to disconnect the battery for 30mins which will trigger the transmission to re-learn its shifting patterns. It may or may not fix the issue but it certainly won't make the problem worse.
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post #7 of 16 Old 09-23-2021, 12:05 PM Thread Starter
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Quote:
Originally Posted by Bilko View Post
Looks nice and clean.

The other zero-cost fix to try for the shifting problem is to disconnect the battery for 30mins which will trigger the transmission to re-learn its shifting patterns. It may or may not fix the issue but it certainly won't make the problem worse.
Should the battery disconnect be done like other TIPM equipped Jeeps, with the positive and negative cables attached together so that all capacitors in the TIPM and other components drain completely? I know the TIPM in the WK2 is a little different than the KK, but connecting the cables can't hurt, I guess. If I recall correctly, the TIPM reset procedure is going to run position (not started) for 12 seconds (KKs gave 2 dings), then off position?
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post #8 of 16 Old 09-23-2021, 12:33 PM
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There are a couple levels of adaptations. Shorting the two cables or removing power for 5 minutes will clear some adaptations, but if you want to reset a NAG to factory you need to run the reset procedure with a scanner:

1.With the scan tool, reset the Transmission adaptives. Resetting the adaptives will set the adaptives to factory settings.

NOTE:
Perform the Coast Down Adaptations first. The Transmission Temperature must be greater than 60C (140F) and less than 70C (158F). Failure to stay within these temperature ranges will void the procedure.

2.Drive the vehicle until the transmission temperature is in the specified range.

3.Perform 4 to 5 coast downs from 5th to 4th gear and then 4th to 3rd gear.

NOTE:
For Upshift adaptation, the Transmission temperature must be greater than 60C (140F) and less than 100C (212F). Failure to stay within these temperature ranges will void this procedure.

4.From a stop, moderately accelerate the vehicle and obtain all forward gear ranges while keeping the Engine RPM below 1800 RPM. Repeat this procedure 4 to 5 times.

5.Obtaining 5th gear may be difficult at 1800 RPM. Allow the transmission to shift into 5th gear at a higher RPM then lower the RPM to 1800 and perform manual shifts between 4th and 5th gears using the shift lever.

6.The TCM will store the adaptives every 10 minutes. After completion of the adaptation procedure make sure the vehicle stays running for at least 10 minutes.

7.It is possible to manually store the adaptives under the 10 minute time frame using the scan tool Store Adaptives procedure.


Since the transmission is always adapting, you could just run the relearn procedure and see what happens.

The WK2 doesn't have the same TIPM reset procedure as the KK. The TCM reset/learn procedure is different, the KK uses a 42RLE transmission similar to the 5.7 545RFE and its relearn procedure.

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #9 of 16 Old 09-23-2021, 01:25 PM
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Where do you get this Info, do you have the full-on service manual?
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post #10 of 16 Old 09-23-2021, 04:08 PM
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Years ago, the NAG1 section of the LX service manual was posted on one of the LX forums. And I do own a 10 year old vintage WK2 FSM and 12 year old one for the KK along with a number of tech articles I downloaded over the years. I always buy a service manual for any vehicle I own. To the chagrin of my spouse, I have quite a collection. Newer models often use the same hardware as older models and older model service info can be better. Nothing is up to date with current revisions, however, like a pro can get with a subscription. Just a hobby of mine.

The service manual is by the book, we all know of shortcuts and details not published there. It also helps to play cards and bowl with a couple techs.

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #11 of 16 Old 09-25-2021, 02:39 PM
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Quote:
Originally Posted by Steve.A View Post
Should the battery disconnect be done like other TIPM equipped Jeeps, with the positive and negative cables attached together so that all capacitors in the TIPM and other components drain completely? I know the TIPM in the WK2 is a little different than the KK, but connecting the cables can't hurt, I guess. If I recall correctly, the TIPM reset procedure is going to run position (not started) for 12 seconds (KKs gave 2 dings), then off position?
My background is in electrical and electronics engineering and connecting the neg to pos just sounds wrong

All the electronics on the vehicle should discharge everything if you disconnect the battery for 30 mins. Some settings are persistent in nonvolatile memory and they do need to be reset using the procedure Coldcase has posted but just a basic reset can help and is worth a try before you invest in a high-end ODB scanner.
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post #12 of 16 Old 09-25-2021, 06:02 PM
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Disconnecting the battery cables from the battery and shorting them together is the old school way of quickly draining the module's power caps, as well as guaranteeing they are drained so a reset will occur on power up with cleared volatile memory. That may not be best practice universally.

In a WK2, after disconnecting the battery ground cable, the caps would drain within a minute, but waiting 5 minutes is suggested by Jeep engineers. Waiting 30 minutes is better.

In a shop, techs rather not wait, time is money.

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #13 of 16 Old 09-29-2021, 08:41 PM Thread Starter
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I bought the WK2 and tried the battery disconnect. No change. I need to get a better bi-directional scanner to attempt to change the NAG1 adapatives, as ColdCase mentioned. I started on the catch up services on the vehicle. One surprise was when changing the differential fluids in the front and rear, the front differential was almost 4 oz. over full. Oddest thing I've seen. When I pulled the fill plug first, it just drained and drained. So much so that I measured it at about 4 oz. I don't know how someone got that much fluid in the diff. I replaced it with Royal Purple 75W140 with the friction modifier in it. The Royal Purple was about the same price as the cheaper stuff and friction modifier combined. I doubt that will make a difference, but found it interesting. I ordered a trans. dipstick and trans. filter today, so will see if that makes any difference after I change it. Someone mentioned my fluid levels may be incorrect, we'll see.
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post #14 of 16 Old 09-29-2021, 09:43 PM
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The friction modifier is required only when there are clutches in the differential. No WK2s have clutches in the front differential. No WK2 Laredos have clutches in the rear differential. Rear differential clutches only come with optional ELSD or Quadradrive.

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #15 of 16 Old 09-29-2021, 09:47 PM
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Overfilling usually happens when people fill the diffs using the vent pipe rather than the fill hole, more is not better, you run the risk of blowing out seals if you overfill. The recommended oil for most WK2s is SAE75W-85, I am not sure if 75W140 will be an issue or not.

The diffs on these vehicles are not usually a problem even at high mileage so I just go with the Mopar oil or Valvoline just because the packaging makes it easier to refill without transfer pumps and all the effort involved.

I have performed many diff oil changes on WK2s but to be honest, the drained oil is always golden so I'm not convinced that it is required. I would do it on a used vehicle because I want to know they have the correct oil and the previous owner had not been to a cheap oil change shop and had the diffs filled or over-filled with low-quality oil.

Check out my recent post

https://www.jeepforum.com/forum/f309...hange-4443311/

The transfer boxes on WK2s seem to suffer from more problems, even though issues are rare its worth performing an fluid change in line with the recommended maintenance schedules if you plan to keep the vehicle for a while.
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