Humming noise when tightly turning steering wheel, only during cold start and go?

[Doubeleive]

I thought that was for g the rear diff (mechanical locking version)

I could be wrong but I thought another member posted a tsb about this same issue being the front diff, maybe it is the rear though.
there is another thread about noise when cold and turning.

 

[B-train]

Interesting thread. Sounds like GM went back to 1990 in their engineering and repeated the process of having to put an additive in the rear diff to prevent chatter, etc when turning.

 

[DenXL]

I had the fluid changed a few weeks ago and they said to drive the truck for 200 miles. If the noise comes back then they said they will put a brand new differential… well I am scheduled to bring the truck next Monday for a new differential…
PS - I own a 2021 Tahoe LS… 25k miles.

 

[VAguy68]

I was having this issue, I took my 21 Z71 in for various maintenance items (90K miles). They changed the fluid with additive and the issue has been resolved.

 

[tomtendo]

I was having this issue, I took my 21 Z71 in for various maintenance items (90K miles). They changed the fluid with additive and the issue has been resolved.

So we just had our 2021 Suburban "fixed" with the TSB about the rear differential fluid. Picked the car up yesterday after they had it for nearly a week AND I STILL HAVE THE MOANING sound when turning! What did you do to get rid of the sound?!

 

[tomtendo]

I had the fluid changed a few weeks ago and they said to drive the truck for 200 miles. If the noise comes back then they said they will put a brand new differential… well I am scheduled to bring the truck next Monday for a new differential…
PS - I own a 2021 Tahoe LS… 25k miles.

We had ours "fixed" with the service bulletin (https://static.nhtsa.gov/odi/tsbs/2023/MC-10230610-0001.pdf). We picked it up yesterday after they had it for nearly a week and we still have the moaning sound.

 

[DenXL]

They ordered me a new differential…. It’s on back order…. The only thing that will fix it is a new differential guys…

 

[WalleyeMikeIII]

Right, but they have to try the fluid first, I bet.

 

[tomtendo]

They ordered me a new differential…. It’s on back order…. The only thing that will fix it is a new differential guys…

How back ordered is it?

 

[91RS]

Right, but they have to try the fluid first, I bet.

Correct.