Joining the rear diff club

[Hunter Mike]

Just found I joined the rear differential club today. 31,500 miles and the rear was making groaning noises at low speeds during tight turns. Brought it in and took the tech for a drive and it didn't make noise(of course). Put it on the lift in drive and listened with a mechanic's stethescope but didn't hear noise because the rear tires were moving at the same speed.

What was noticed is the pinion(input) seal was leaking. It was flung from the spinning driveshaft and pretty well covered the rear. Last time I was under it in March with 22k on it and it was dry. A quick pull of the fill plug showed it still had fluid. It was definitely hot as I had about 200 miles on it today. A quick hand press felt like it was over 150F but not hot enough to burn. Tech is going to research and I go back Tuesday to find out if the pinion seal is replaceable or I get a new diff.

Looks like the pinion seal is replaceable but if the gear has play, the entire differential needs replacement as "The pinion is fitted in the final drive gear's left-hand housing and cannot be replaced."

 

[Hunter Mike]

 

[BenD]

Is grease on the right ?

 

[Hunter Mike]

Is grease on the right ?

Nope, all gear oil that leaked and was slung by the rotating pinion gear oil slinger...good name for it, huh?

 

[Hunter Mike]

Brought my car in for the appointment to replace the pinion seal and this time it made the noise for the tech during a test drive(yay!). He contacted GM technical and they approved the replacement of the rear diff. Just turned over 33k on the way home and the noise is definitely not getting better.

Tech suggested I get some spirited driving out of the way to get the most use out of this diff

The symptoms happened at low speed while turning right. A groaning noise from the rear could be heard and it was speed dependent during accel and decel. Shifting into neutral caused the noise to go away and we agreed that the input to the rear diff was shut off while in neutral.

 

[Pacer69]

Sounds like a very common factory defect that's going to hit a lot of us. Wonder if they'll extend the warranty for this issue?

 

[Jmlo96]

For those of you who had rear diff issues, did you have a vibration at highway speeds? Once I hitt 75 I start to get a vibration. Gets real bad around 85-90. I have heard the groaning noise from the rear once. I have also felt a vibration 2 times that felt like driving on rumble strips.

 

[MMKRegalTX]

I can't with this car anymore...i have had a few new cars before and never had a recall or issue with any of them, but this one just keeps coming up with more and more issues.

 

[Hunter Mike]

For those of you who had rear diff issues, did you have a vibration at highway speeds? Once I hitt 75 I start to get a vibration. Gets real bad around 85-90. I have heard the groaning noise from the rear once. I have also felt a vibration 2 times that felt like driving on rumble strips.

Smooth as silk up and over 120...kph of course 😉

 

[Map18TTourX]

For those of you who had rear diff issues, did you have a vibration at highway speeds? Once I hitt 75 I start to get a vibration. Gets real bad around 85-90. I have heard the groaning noise from the rear once. I have also felt a vibration 2 times that felt like driving on rumble strips.

my car didn't have an vibrations..

you might have tossed a wheel weight. Or maybe the foam on the inside of the tire is pealing away..

 

[mike69440]

Amsbury Chevy.
23K miles.

So you are just over the border from MA?
Did you get the diff replaced?

 

[Map18TTourX]

So you are just over the border from MA?
Did you get the diff replaced?

i am in Londonderry.

Mine was replaced for a humn while costing on the Hwy... But the noise is still there.. So i don't think it was the rear diff. They just replaced it for shits and giggles i think..

 

[Jmlo96]

my car didn't have an vibrations..

you might have tossed a wheel weight. Or maybe the foam on the inside of the tire is pealing away..

Good suggestions, thank you. My factory Conti Silent tires are long gone. Someone had put an illegal plug on one of the sidewalls before I bought the car. Conti DWS06 replaced them. 2 thousand miles in and I've had vibrations since. I'm going to have Discount Tire roadforce balance the tires this weekend.

 

[jdoodle]

Noticed the rear diff on driver's side covered with oil enough that it would drip a few drops on driveway while installing my trailer hitch. No strange noises associated with it. Have appt. in two weeks to get it looked at (had to wait two weeks to get a loaner car). Checked drain and fill plugs and both tight. We'll see if I can join the rear diff club. 2018 TourX, 8K miles.

 

[Hunter Mike]

PTU replacement today went well. I was able to hang out and chat/help/get in the way of the tech. Found a few shortcuts to save some time. Checked the alignment after and it was still fine. Quiet on the way home so we'll see how long this one lasts.

Not really a DIY job as it needs programming. We swapped over the old controller but since it has adaptive learning for the clutch it needs to be reset.

I will post again in my rear diff fluid DIY thread but I do not recommend using any fluid other than the official ACDelco Dexron LS. From the repair data:

"Installation of the incorrect type gear oil may create a "moan" type noise within 7 770–25 900 km (3–10,000 miles). Fluid that is "black" in color is to be considered normal and is darkened by the carbon material in the clutch plates."

 

[Jmlo96]

PTU replacement today went well. I was able to hang out and chat/help/get in the way of the tech. Found a few shortcuts to save some time. Checked the alignment after and it was still fine. Quiet on the way home so we'll see how long this one lasts.

Not really a DIY job as it needs programming. We swapped over the old controller but since it has adaptive learning for the clutch it needs to be reset.

I will post again in my rear diff fluid DIY thread but I do not recommend using any fluid other than the official ACDelco Dexron LS. From the repair data:

"Installation of the incorrect type gear oil may create a "moan" type noise within 7 770–25 900 km (3–10,000 miles). Fluid that is "black" in color is to be considered normal and is darkened by the carbon material in the clutch plates."

I had put 75w85 Redline in my rear diff and ran it about 4k miles. I was starting to get the moaning noise. I switched back to the factory Dexron LS and everything is great.

 

[jdoodle]

Just got my TourX back today. Took it in Monday and picked it up earlier today (Weds). They replaced the seal. Will keep an eye and ear on it. In the "silver lining" dept, they gave me brand new Malibu LT to drive. Thanks to Covid I had a mask on and nobody could tell it was me. 😈 Not too impressed with the Chevy.

 

[dsimoneaux19d]

Good day everyone,

Looks like I will be joining the rear diff club as well. Purchased the car October 2019 and its been great. We went on a road trip in late July and started noticing it on the way back, now there is no hiding the howl during a low speed right or left hand turn and there is even some chunk on acceleration from a stop.

Its at the dealer now but they are saying that there is no documentation from GM on this being an issue. Did anyone get any kind of TSB # or anything? They only thing the service rep said was that Corvette's have a similar issue but the recommendation is to service the rear diff.

2019 Tour X Essence
22,000 miles

 

[BenD]

At the beginning of the medicine.....you have a broken leg.....hummmm.....sorry can’t help you, we have no reference for that kind of injury!!!!!

 

[Hunter Mike]

Its at the dealer now but they are saying that there is no documentation from GM on this being an issue. Did anyone get any kind of TSB # or anything? They only thing the service rep said was that Corvette's have a similar issue but the recommendation is to service the rear diff.

2019 Tour X Essence
22,000 miles

Completely different differential as ours is sourced from GKN and is mechanically different.

There doesn't need to be acknowledgment from GM or a TSB as you're having an issue that can be reproduced. TSB's are issued when there are enough failures and help guide the dealer toward the correct repair.

My tech sent an email to GM's technical line and was told to replace the differential under warranty. My pinion seal was leaking and that's serviceable in the field. The diff is not field-serviceable so it got replaced.

Sounds like you need a new service writer or escalate it to the service manager.