Rear Differential shudder when turning under acceleration
Hello, this shop and vehicle are on the 3rd differential ( USED Units) for this problem. No codes. Please watch video to see the condition, note if you turn up bass you may hear. If I unplug the rear diff pump the problem goes away. Note that tires are all the same size, I was called to reflash rear diff? The dealer told them it has to be programmed? I am not aware of this, the DTCM has the latest calibration. I did ECU reset on ecm,tcm,dtcm, and proxi alignment, also I performed the rear diff bleed procedure and verified proper fluid and level, all tires same size and manufacture and in decent shape.
Any help or ideas on how to isolate root cause appreciated, we do have wi tech for diag.
Note that some diagrams show a rear drive line module that they state is on the rear diff, we do not have this present of see where it is suppose to be located. UPDATE witech shows vehcile not equipped with RDM diag.net/file/f1yj8l4y2…
Is the rear diff an assembly with the pump and clutches, and was that all replaced as a unit?
2 used rear diffs. All have same problem as the original complaint. Story goes noise started when backing up and turning out of driveway.
Same complaint immediately after diff swap or drive awhile and then return?
Never returned to customer same sound / concern according to tech that originally inspected / repaired
I may have some diag literate on that rear differential I will look see where it is and get back to you
No totally different unit, more like a traditional rear diff for independent rear suspension. I should have taken pics of units on the floor.
I worked on one of these recently with what seems like the same issue. i tried several things and the only thing that helped was add a tube of friction modifier from the parts store such as Autozone. And it got rid of 75% of the noise/shudder. possibly A brand new one would fix 95% as I believe these always have a slight binding being awd.
I am going to recommend some friction modifier , do you recall brand that worked.
Part No. 402508 This is the part # from advanced auto parts. It’s a white and blue tube called trans x posi trax
When you say no codes, does that mean all computers? I would try graphing all 4 wheel speed sensors.
yes no codes entire vehicle ( surprising I know! ) I did not graph all sensors, I did monitor the 4 bussed speed sesnor inputs and they seem good, NOTE that with snap on scanner erratic readings, at 20MPH reading aprox 120mph, this is when shop called me, note that witech all 4 bussed sensor inputs are matching vss.
I think there are two possibilities. Either this is a pattern failure of the rear diff assembly, and the used ones have the same problem, or the control module isn't controlling it properly. Is there any scan data available for that system to see if the module is receiving some faulty input signal?
Hello Steven, There is a large amount of data In the DTCM , I am trying to figure out what to look at! as stated above the bussed wheel speeds seem fine looking at digital data pid, I will graph next time at shop, in my mind trying to figure out why only when turning & accelerating. I am no sure if you heard on video but will happen when hard on brakes and turning as well. I am thinking…
Does that diff have vent tubes that go to it? If so I would blow them out and see if the noise goes away. I’ve had Land Rovers with that issue. Usually Makes noise when pulling out of parking spaces and on hard turns.
I personally have had at least 2 Cherokee's with the 3.2 V6 an AWD with the identical symptoms you seem to have, that had wallowed out CV shaft joints. Put the car on hoist an wiggle the CV joints. May have to replace them all. The fronts were the worst on the ones I did because obviously they turn as well. Just an idea.
Brian We have a Jeep we use as our shop vehicle. Intermittently, it has had a grown from the rear differential for a while. To fix it, I have the guys drain the gear lube. We then fill with new gear lube and then add one small bottle of Mopar friction modifier for the rear differential, works well, groan gone for a while.
1st I see that the PCM and TCM have updates available. I have a 12 grand Cherokee with the same complaint. There is an update I think to the PCM for a customer complaint of what you are describing. I would start with the updates and change fluid add friction modifier as needed. I also believe the service interval on the rear diff is 30K so more than likely a fluid change and friction modifier…
I know there are updates for the TCM and PCM, I did look at the tsbs that witech / tech authority displayed, they did not relate to this concern that I had seen, I may head back to shop and update so we can eliminate software.
UPDATE on this vehicle, The shop was in contact with local dealer that stated they know of a problem with the PTU causing this isssue and an extended policy to correct it? I will let you all know what I find out.
Ok just received word dealer did not do anything with the PDU/ transfer case. They replaced the rear end and both rear drive axles and problem is gone, they did charge for this and it was not covered under warranty from what I was told. There was nothing wrong electrically or with programming. Lessons learned : A different part is not always a good part (again as if I have not been here…
Nice. Did you ever happen to check the axles to see if the joints where loose like I asked about?
No, unfortunately I was already offsite, and when I was scheduling to return they already had taken to dealer under assumption "free " repair. Being mobile makes follow up tough..