Hey, I have a 2020 cherokee trailhawk, having some issues. Warranty is up in 2 weeks, took it to the dealer for transmission issues, paint bubbling rear diff leak and driver side output bearing (cv axle wobbles alot). Dealership came back and said all that was wrong was axle seal and transmission update. The transmission would lose gear on take off, Rev up and then bang into gear, felt like being rear ended, they said update would fix it. Rear diff leak caused by output seal, but they didn't say anything about the top of diff. Anyone have issues like this and what was the outcome.

Hey Nick,

Welcome to the Forum!

Ok, so I'm going to take this out of order...


1. Yes, get those transmission updates. The majority of transmission issues can be traced to missing a software update. If the shifting is still bad afterwards, have them reset your transmission to factory detail values (called the "adaptive values").

2. Now, yes, the rear differential (called the Rear Drive Module or "RDM" on the Cherokee), often leaks on the driver's side. It's due to the shaft inside the RDM being substantially shorter (about 6 inches) than the one on the right side (which is about 24 inches). As a result, you'll notice a lot of up & down play on the driver's side that's not present on the passenger side. That's actually normal. The seal on the drivers side wears quicker and needs to be replaced as you'll weep oil from it. Note, that while the corrective action is replacing the seal, if funds are tight, another valid option is just adding more gear oil (70W-80) to the two fill plugs on the rearward-facing side of the RDM. Will you have the weep still? Yes, but as long as you periodically add additional gear oil for that which is lost, there's no negative result.


To add oil, you need a 3/8" ratchet. Your Trailhawk as 2 fill plugs as shown in the photo below with the "1" and "2". Fill both to the bottom lip of the fill hole using Mopar 70W-80 gear oil.

3. Here's what the weep looks like. Yours is probably the same. Many of us have it.

New seal (left), old seal (right). Seal (Part below). Dealer or any mechanic can replace it.

This is your Left-rear halfshaft (yellow) and note, there's only a 6" stub shaft that enters into the RDM (red). Because of the shortness, it only goes through one set of bearings hence even when fine, there's substantial up & down play. This is normal. If you do a Search in this Forum, you'll actually find members who have posted

Here's a video of abnormal shaft wobble. Again, on a Cherokee, there will be some wobble though. https://www.jeepcherokeeclub.com/th...y-output-shaft.252063/?post_id=3068092&nested_view=1&sortby=oldest#post-3068092

Here's another one that's a bit much play: https://www.jeepcherokeeclub.com/posts/3044549/



4. Regarding the top leak leak, there's a black top plate and then under that a blue seal that seals a hydraulic fluid reservoir the RDM uses to engage its internal clutch for the 4WD to work. Now, the only real thing that can leak there is probably if the black top cover rusts through, it could happen. However, one thing I noticed in your photo is there's fluid around the small vent tube extension. (see red circled area in the photo below). I wonder if your rubber vent hose has backed-off or isn't tight and fluid came out the junction where the rubber hose is on the nipple (vent tube extension). You'd need to make that call - just for good measure, possibly see if that can be pushed on further. Either way, if the fluid does get too low one day then what will happen is you'll get a message on your instrument cluster that says "SVC 4WD". If the fluid gets too low the RDM won't be able to build enough pressure to engage the 4WD. So, one option is to live with it now (knowing one day the fluid may need to be topped-off and probably, the top plate replaced) or do it now.

Hope some of this helps...

 

Hey Nick,

Welcome to the Forum!

Ok, so I'm going to take this out of order...


1. Yes, get those transmission updates. The majority of transmission issues can be traced to missing a software update. If the shifting is still bad afterwards, have them reset your transmission to factory detail values (called the "adaptive values").

2. Now, yes, the rear differential (called the Rear Drive Module or "RDM" on the Cherokee), often leaks on the driver's side. It's due to the shaft inside the RDM being substantially shorter (about 6 inches) than the one on the right side (which is about 24 inches). As a result, you'll notice a lot of up & down play on the driver's side that's not present on the passenger side. That's actually normal. The seal on the drivers side wears quicker and needs to be replaced as you'll weep oil from it. Note, that while the corrective action is replacing the seal, if funds are tight, another valid option is just adding more gear oil (70W-80) to the two fill plugs on the rearward-facing side of the RDM. Will you have the weep still? Yes, but as long as you periodically add additional gear oil for that which is lost, there's no negative result.


To add oil, you need a 3/8" ratchet. Your Trailhawk as 2 fill plugs as shown in the photo below with the "1" and "2". Fill both to the bottom lip of the fill hole using Mopar 70W-80 gear oil.

View attachment 244753 View attachment 244754
View attachment 244755 View attachment 244760




3. Here's what the weep looks like. Yours is probably the same. Many of us have it.

View attachment 244756

New seal (left), old seal (right). Seal (Part below). Dealer or any mechanic can replace it.
View attachment 244757

View attachment 244758


This is your Left-rear halfshaft (yellow) and note, there's only a 6" stub shaft that enters into the RDM (red). Because of the shortness, it only goes through one set of bearings hence even when fine, there's substantial up & down play. This is normal. If you do a Search in this Forum, you'll actually find members who have posted

View attachment 244759


Here's a video of abnormal shaft wobble. Again, on a Cherokee, there will be some wobble though. https://www.jeepcherokeeclub.com/th...y-output-shaft.252063/?post_id=3068092&nested_view=1&sortby=oldest#post-3068092

Here's another one that's a bit much play: https://www.jeepcherokeeclub.com/posts/3044549/



4. Regarding the top leak leak, there's a black top plate and then under that a blue seal that seals a hydraulic fluid reservoir the RDM uses to engage its internal clutch for the 4WD to work. Now, the only real thing that can leak there is probably if the black top cover rusts through, it could happen. However, one thing I noticed in your photo is there's fluid around the small vent tube extension. (see red circled area in the photo below). I wonder if your rubber vent hose has backed-off or isn't tight and fluid came out the junction where the rubber hose is on the nipple (vent tube extension). You'd need to make that call - just for good measure, possibly see if that can be pushed on further. Either way, if the fluid does get too low one day then what will happen is you'll get a message on your instrument cluster that says "SVC 4WD". If the fluid gets too low the RDM won't be able to build enough pressure to engage the 4WD. So, one option is to live with it now (knowing one day the fluid may need to be topped-off and probably, the top plate replaced) or do it now.

View attachment 244761


View attachment 244762


Hope some of this helps...

I don't know if that would explain the full 360 degrees of moisture around the top housing. I would be very concerned about your hydraulic fluid leaking – there's a pump that pressurizes the fluid – I could see a bad gasket or as Gary mentioned the metal plate itself not having a proper seal.

 

Ya I wasn't sure about the cv axle wobble. Don't have much trust in the dealer I brought it to. They came back and said only the axle seal was gone. I do all the work on all my vehicles, only reason I brought the jeep in was for the warranty work, noticed the leak and wobble so I brought it in. They said they had it all apart but didn't have the seal in stock so I have to bring it in this week. I mentioned the top of the diff leaking as well and they said they didn't notice any wet spots or leaking on the top. They also mentioned the rear brakes were installed wrong, (missing the clips and i should have them replaced) as soon as I got home i took everything apart and nothing is missing. Wonder if it was even my jeep they looked at. I used a scope and took pics of the top and it doesn't look to good, the tops all corroding under the cap and actuator

 

I would take it back with this evidence asap. Or visit another Jeep dealer that’s more competent. Get it looked at and verified stat before warranty is up.

 

Yes I was debating on going to another dealer and seeing what they say. I also asked about paint bubbling on all doors and hood. No paint chips causing it. They said i have to take it back to the dealer i purchased it from, which is 5 hours away. Probably better off going to another dealer and seeing what they say.

 

Yes, show them the photo.

 

It’s crazy to think they made the rear diff because that’s what I know it as so complex it’s got to be updated with software, and those gaskets busted for being a 2020 5 years old now how is one side of the shaft shorter than the other

For the dealer to say they can’t change the fluid out is truly a racket on Chrysler.

If your warranty wouldn’t cover it I would find a reliable independent shop that would do it. Let them drain and fill the front and rear diff and the ptu and let them update it. I was going to do it myself until I saw how complicated Chrysler made it. I honestly think any of this lifetime nonsense is a marketing scheme. When they started the Cherokee in 2014 they told everyone its lifetime fluid for this and that and people bought it and you know what no wonder why we learned years later nothing is forever. I’m also realizing with the transmission when you do a drain and fill to reset the tcm either the gas pedal and ignition method or disconnect the battery for 30 minutes that I can understand. But diffs and a transfer case being so complicated I can’t understand.

 

Just dropped it back off at the dealer. They emailed and said they wont put the leak on top of the diff through warranty as they would be charged back for the work because they know it would not be covered under warranty due to environmental damage, 60,000kms, really. The jeep has 60,000 kms on it, driven in the winter maybe 4 times, it's parked in a garage. Figured buying a new jeep was a good idea, but seems like jeeps are garbage with all the issues, especially with 60,000kms on it.

 

it would not be covered under warranty due to environmental damage, 60,000kms, really.

WTF is "environmental damage"???🤔🫤😳

 

No idea, I'm in canada, I've sent an email to fca about the issues.

 

I'm guessing that means anything other than a manufacturer defect in parts or workmanship.

For this case, I guess they're saying moisture (environmental) has possibly rusted the lid or something like that.

Owner didn't store their car in a vacuum chamber each night!