AWD Makes Noise Near Rear of Car when Turning at Slow Speeds

[Hunter Mike]

Update to my DIY above. I would not recommend using anything other than the ACDelco Dexron LS gear oil.

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."

 

[kevjam79]

Get the welder out and weld the b!+<h!!!!



Having a little fun... hoping for the best for you guys...

 

[knight001]

Hi all....

So just had the 24,000km service (nearly 15K miles) and took my car away for a weekend getaway.

So now that I’m back I had noticed a noise coming from the rear when I’m driving and turning right majority of the time.

Also if I’m feathering the accelerator pedal or reversing low speed.

I took my car in for service and the service technician noticed it straight away. He told me that he has had few in now for this issue and Holden (GM) advised to replace gear oil.

Picked the car up and the sound has gone. Feels a lot better to drive however at low speed and entering a mild incline the car feels sluggish and I feel the need to put my foot down to go back a gear.

I know that this could be related to the factory tune in the transmission as I have read about this elsewhere in car reviews where it was noted that while it is a good transmission it can be sometimes be lazy to kick back at low speed and small inclines.

I guess that I did not notice it as much before and wonder if the diff issues which seem fixed with the oil change had anything to do with it?

Maybe the transmission needs resetting? (Not sure how to do that) or could something else be acting up? Or perhaps a better transmission tune is in order...

Other than that... It’s a dream to drive!

2019 ZB Holden Commodore VXR.
Cheers... Tim

 

[Hunter Mike]

Most likely the technician reset it and now it doesn’t know how you drive. Its not normal to do this during a fluid change so I’m sure why it would change. Give the adaptive learning some time. There isn’t a way to clear the transmission yourself unless you have a dealer-level scan tool.

 

[knight001]

So.....I just wrote a ticket on my car (2018 GS 17000 miles) last week and had our techs check it for this EXACT concern. Ultimately, the rear diff fluid was just changed out. However, my tech came to my desk and told me to come take a look at something when he drained the fluid. In all the years I have been writing service, I have always known Diff fluid to be clear or brown, depending how dirty the fluid is. What I saw come out of my rear diff was JET BLACK. Neither my tech or myself had ever seen this before. He said GM was telling him to just change the fluid. He told me if the sound came back, we would just replace the rear diff. Here is a screen shot of my complaint and his diagnosis. As black as the fluid was, im expecting we will be replacing the rear diff down the road
View attachment 18693

Hello… Just a question. How is your car now that the fluid was changed? I noticed a lot of people have had their diff replaced and some just had fluid changes. I had this issue and (GM Holden) recommended fluid change which took the sound away.
Just wanted to know how things are going or if the sound ever came back?
The only thing I have noticed since the fluid change is that unless it’s another issue I feel that the car is sluggish in moderate inclines or feels like it’s lugging up hills sometimes to which I feel I need to put my foot down more to make the car kick back a gear to bring the revs up.

 

[JORDANSILVERNAIL]

Hello… Just a question. How is your car now that the fluid was changed? I noticed a lot of people have had their diff replaced and some just had fluid changes. I had this issue and (GM Holden) recommended fluid change which took the sound away.
Just wanted to know how things are going or if the sound ever came back?
The only thing I have noticed since the fluid change is that unless it’s another issue I feel that the car is sluggish in moderate inclines or feels like it’s lugging up hills sometimes to which I feel I need to put my foot down more to make the car kick back a gear to bring the revs up.

I have no more complaints there. The sound never came back and I haven't noticed any performance issues. The only concerns I have now is with the transmission. As odd as it sounds.....I hope my transmission totally fails under powertrain warranty 😆 I want a new transmission badly. I'm convinced that will take care of all my concerns. I'm at 46K now

 

[knight001]

I have no more complaints there. The sound never came back and I haven't noticed any performance issues. The only concerns I have now is with the transmission. As odd as it sounds.....I hope my transmission totally fails under powertrain warranty 😆 I want a new transmission badly. I'm convinced that will take care of all my concerns. I'm at 46K now

What sort of issues you having with your transmission?

I’m glad the diff sound are gone… 🙂

 

[Jack GS]

What sort of issues you having with your transmission?

+1

It seems like the policing Commodores (also V6 w/9-speed) in Australasia are having some trans issues too. Seems to be fairly isolated though and you're the only one to mention any issues on the forum @JORDANSILVERNAIL.

 

[JORDANSILVERNAIL]

What sort of issues you having with your transmission?

I’m glad the diff sound are gone… 🙂

Intermittently during hard acceleration from 1st gear (usually when rolling in 1st and turning out into traffic 😳) the gear slips and rpms red line and vehicle has ZERO acceleration. If I left off the gas for a couple seconds( that's a couple seconds too many for me), it catches and will take off again. If I stay on the gas or pop the gas pedal, the car goes no where and rpms max out. I have to just fully let off the gas and let it catch.
Oddly enough, this also happens when rolling down hill with ZERO throttle and then LIGHTLY trying to take off when the road levels back out. As an example: When leaving my work, I have to sit at a light on a driveway with a STEEP incline. When the light turns green, I don't FULLY let off the brake so my front end doesn't bottom out. Once my front end is clear, I'll lightly accelerate and the rpms just shoot up and I'm barely moving in the middle of the intersection. I let off the gas for a couple seconds, boom. it catches and goes.
Last, this damn whine. It happens when down shifting at 30 mph and again at 20 pmh. The whine continues until the next down shift and then stops. My tech thought it was my rear diff. turned out it wasn't. This has been going on since around 5k miles. Its more annoying than anything, but I can't help but feel its related to the slippage.

 

[JORDANSILVERNAIL]

+1

It seems like the policing Commodores (also V6 w/9-speed) in Australasia are having some trans issues too. Seems to be fairly isolated though and you're the only one to mention any issues on the forum @JORDANSILVERNAIL.

I feel like just because I've written service for so long, anything out of "the ordinary" really stands out to me. It probably doesn't help that I like to ride with windows down and no music a lot of the time. My tech keeps telling me I need to just listen to loud music more. Funny, not funny. ha

 

[Ultima1987]

Add a Plus One to the differential groan. Mine started at 36000 or so. Sitting at the dealer now to see what they come up with.

 

[Buckjoe]

Based on your post I changed the rear diff fluid in the TourX this morning. I love the smell of sulphur in the morning! Car has 6003 mostly highway miles.

The change is pretty easy except the rear sway bar is pretty close to the fill plug. Not enough room for a 10mm hex socket, I had to break out the old trusty Craftsman ball-end hex wrench.
View attachment 18716View attachment 18720

They are only tightened to 18 ft-lbs so the fill and drain plugs came out easy. My fluid wasn't pitch black and looked pretty good. The drain plug magnet was another story. I think it was pretty maxed out with ferrous material.
View attachment 18721
View attachment 18717View attachment 18718View attachment 18719

Overall a pretty easy job for anyone and only one tool was needed. It took right at a quart of Dexron LS fluid(capacity listed as 0.92qt). P/N 88862624 from GM. I used some Castrol 75W-90LS fluid that I had laying around and will report back if it doesn't get along with the clutches. I will probably change it every time I change the transmission fluid since it's easy and inexpensive. If you have a shop do it I would guess 1 hour of labor.

Edit: after a brief test drive with figure-eights on and off throttle I notice no issues using the Castrol fluid with LS additive in it. The OE fluid from GM is around $15 so it’s not as bad as the front PTU fluid at $50/qt! Must be unicorn tears.

Soooo, the rear differential was moaning, and popping under hard acceleration. Changed the fluid today. Drain plug magnet had 1/16” of black goo. Diff was covered in grime. Only drained >600cc old fluid. Opaque amber with fine silvery tones. So, I added the appropriate lube until it dripped. Cleaned everything with a whole can of Brakleen after I was done. Quiet as a mouse now. I’ll follow up with results over time. And, yes, I know the diffs are the Achilles heel for these cars.

 

[2018 TourX in Texas]

Soooo, the rear differential was moaning, and popping under hard acceleration. Changed the fluid today. Drain plug magnet had 1/16” of black goo. Diff was covered in grime. Only drained >600cc old fluid. Opaque amber with fine silvery tones. So, I added the appropriate lube until it dripped. Cleaned everything with a whole can of Brakleen after I was done. Quiet as a mouse now. I’ll follow up with results over time. And, yes, I know the diffs are the Achilles heel for these cars.

Good to hear your changing fluid 'fixed it'.
How loud was the moan and at what speeds ? Turnng & Straight ahead ?
I had the moan noise upon turning at parking lot speeds both directions.
I had 5,000 miles earlier changed to GM 88862624 LS 75/90 Gear Fluid as recommended.
Funny the noise cropped up only a short while later.
I had saved the prior Gear Lube drained out - it looked SO perfect.

So, I just drained the old GM LS fluid (again, only 5k miles on it) It was super nasty black like the WORST DIFF fluid you could imagine !

I filled back in the original clean looking Diff fluid (exact type unknown; just had driven the car 15,000 miles on it since purchase) and VIOLA car back to normal, no noises just as before.

Still not sure what's going on. Please see my posts towards bottom of page 17 of the "Join the Rear Diff Club" thread for pictures etc.

Cheers - David in Texas

 

[Buckjoe]

Good to hear your changing fluid 'fixed it'.
How loud was the moan and at what speeds ? Turnng & Straight ahead ?
I had the moan noise upon turning at parking lot speeds both directions.
I had 5,000 miles earlier changed to GM 88862624 LS 75/90 Gear Fluid as recommended.
Funny the noise cropped up only a short while later.
I had saved the prior Gear Lube drained out - it looked SO perfect.

So, I just drained the old GM LS fluid (again, only 5k miles on it) It was super nasty black like the WORST DIFF fluid you could imagine !

I filled back in the original clean looking Diff fluid (exact type unknown; just had driven the car 15,000 miles on it since purchase) and VIOLA car back to normal, no noises just as before.

Still not sure what's going on. Please see my posts towards bottom of page 17 of the "Join the Rear Diff Club" thread for pictures etc.

Cheers - David in Texas

The ‘moaning’ was L/R turns at speeds <25 mph, easily noticeable . The ‘popping’ was during hard acceleration. I thought it might have been bag spark plugs. 🤦🏻‍♂️ I bought one of those pump gizmos, worked well. I cleaned the differential so I can see where it seeping in the near future. I’m crossing my fingers that the low lube level was the problem. 😬 I’m guessing it might crop up again in 8600 miles…..we’ll see.

 

[Bluedog69]

Hello
I’m changing my rear differential oil due to a moan sound
I’m using

PRO GEAR 75W-90 (100% PAO ESTER) | Penrite Oil

Pro Gear 75W-90 is a premium full synthetic, SAE 75W-90, heavy duty gear oil that uses 100% PAO ESTER base oils, with an advanced additive system to provide the ultimate performance and protection under all operating conditions. It meets the performance requirements of API GL-5/GL-6/MT-1 as well...

penriteoil.com.au

Hope it’s ok to use
Edit
Well I changed it anyway, the oil wasn’t black and not too much on the magnet
I’ll see how it goes