[db2022cs]

So, I have just passed 40k miles on my 1LE 6MT. According to service manual, rear diff fluid change is I think at 45k. I did the initial fluid change at 1500 miles for the diff. Besides that, oil change always done on time and other maintenance taken care of. There is a squeak in the rear end that pops up once there is heat in the car. It's almost like a squeaky Styrofoam sound. I think it may be exhaust rubbing something. I also think my NPP valve on the driver side is squeaky. I just bought quick jacks so I'm going to get under the car and look at clearances. This is a minor issue and I don't think is related to the issue I am a bit worried about.

When I first drive my car after it sits for a while, I have noticed what feels like abrupt tramlining from the rear end. It only happens on slow sweeping turns, and occasionally on straights with very slight steering adjustments. It goes away after driving the car for a while. I have taken car to a trusted mechanic and they say the car looks and feels solid. They test drove it but only after I had already driven it for a while. It feels like the diff is binding up honestly. Has anyone had this issue at all or something that sounds similar? I actually bought stuff to do my diff fluid a bit earlier than planned, I'll be doing it this coming weekend, along with transmission fluid and oil/filter. Once the car is heated up, the car runs and acts great, but I have lost all confidence in the car currently and I have barely driven in since I have had this issue crop up a few months ago.

[bishopts]

I know the manual trans is a little clunky feeling going through the gears when they are cold. Could be just friction material sticking and releasing while in the turn while the fluid is cold. I wouldn't be surprised if a fluid change makes it less pronounced but doesn't eliminate it. Kind of like a "normal but unwanted characteristic" of the rear end.

[beowulf556]

I feel like you answered your own question… car needs to warm up.

[dpevans]

You have a 1LE eLSD menu in the performance section it shows eLSD slip and see how it's reacting to turning left and right, it shows real time coupling. Look at it and see if it's working properly. I would also check the fluid level you might have a seal leaking. Haven't heard of any issues with the rear end on newer cars. I can tell mines working every time I pull out of my driveway when one tire leaves the ground.

[db2022cs]

Originally Posted by dpevans

You have a 1LE eLSD menu in the performance section it shows eLSD slip and see how it's reacting to turning left and right, it shows real time coupling. Look at it and see if it's working properly. I would also check the fluid level you might have a seal leaking. Haven't heard of any issues with the rear end on newer cars. I can tell mines working every time I pull out of my driveway when one tire leaves the ground.

So, I did my diff fluid change yesterday, fluid was filled up to the fill port. Fluid looked really good, little bit of sludge on the magnetic drain plug but what I would assume as normal. That is the one thing thing about the eLSD that I am a little worried about, the display seems to display weird numbers. It will occasionally blip up to 100% when coasting or not really on throttle rarely, the rest of the time it will sit at 2% and occasionally on a long stretch drop to 0% and eventually goes back up. I think I might have to take it to dealership to look at.

[cdb95z28]

https://gm-techlink.com/?p=11291

[db2022cs]

Just going to write up progress on this. Did my fluid change over the weekend, fluid looked really good, still red in color, no debris or anything in fluid, little bit of sludge on magnetic drain plug but it looked like normal amount. Problem still persisted after doing this change. Earlier today I took it to the dealership and one of the mechanics I have worked with there, who actually has a 2019 1LE took it for a quick spin with me in car. The car was sitting for about 5 minutes while I was chatting with service guys. Within the first little turn we took, the eLSD display was all over the place as the unsettling feeling took place and the % jumped up to 100% then down and bounced around. Once we drove for a couple minutes, the eLSD display would stay at 2%. It would eventually drop back to 0% when going at a steady speed, as soon as you speed up it would kick back up to 2%.

One funny thing we noticed, but we weren't sure, in neutral, while stopped, giving the car a bit of rev's would actually indicate on the eLSD screen that something was going on with the eLSD. I will be dropping the car off on Monday to have the car looked at more thoroughly. I was told it's possible the actuator that purges the system of air may have failed letting air into the system. Could also be some sensor not behaving. Giving the car some beans and the eLSD looks like it behaves perfectly fine and does what it's supposed to do. Hopefully I can get it figured out.

[cdb95z28]

Doesn't sound far from what GM says in the link I provided.

What tires are you running? And when was the last time you had the alignment checked?

[db2022cs]

Originally Posted by cdb95z28

Doesn't sound far from what GM says in the link I provided.

What tires are you running? And when was the last time you had the alignment checked?

If you are saying this is normal behavior, it's not. Spiking up to 100% on that display means full lock right, if it's on a turn, it should not do that from my understanding on how the diff should work. I could be wrong though, that is why I am getting dealership to look at it. If you were in the car with me and felt what I feel when driving, you would be a bit concerned too.

I had my alignment done a couple weeks after running into this issue. I'm running Conti extreme contact sport 02's. Stock sizes.

[dpevans]

My rear end fluid is not red it's clear. AC 10-4034 has the friction modifier.