Differential Whine Question

[techbiker]

I have been hearing what sounds like differential whine on my 2011 RWD PPV Tahoe. I just realized the whine only happens while turning (either direction) AND accelerating at the same time. I don't hear any clunking. The differential is quiet while turning off throttle or when accelerating in a straight line.

I recently replaced the differential fluid with new "grape" GM fluid. Do I need to add a friction modifier, is this noise normal, or does it sound like I have a more serious differential issue?

Thank you very much

 

[PG01]

I have been hearing what sounds like differential whine on my 2011 RWD PPV Tahoe. I just realized the whine only happens while turning (either direction) AND accelerating at the same time. I don't hear any clunking. The differential is quiet while turning off throttle or when accelerating in a straight line.

I recently replaced the differential fluid with new "grape" GM fluid. Do I need to add a friction modifier, is this noise normal, or does it sound like I have a more serious differential issue?

Thank you very much

Which rear do you have?

 

[techbiker]

Which rear do you have?

Whoops, I should have mentioned. I have a 3.08 rear with G80 locking differential.

 

[PG01]

Whoops, I should have mentioned. I have a 3.08 rear with G80 locking differential.

You need the friction modifier, dont care what bottle says or book says. Get a bottle and you'll be good. Fluid is up to bottom of plug hole right? You’re gonna have to drain some and the add it.

 

[swathdiver]

Time to rebuild your differential. Could be worn axle splines but more probable spider gears and side gears and pinions.

The grape scent GM differential fluid has the posi lube but that makes a chattering sound when more is needed; at least it used to.

 

[techbiker]

Thanks for the help.

I'm not sure if it helps, but I am getting some radial (mostly vertical) play in my rear wheels. When I changed my differential fluid last, the gears looked OK. I didn't see any granules in the old fluid.

I will try adding some friction modifier first to see if it quiets things down. Alternatively, do you think both of my rear wheel bearings could be bad? I've heard that bad wheel bearings typically make a growling noise, note a whine. I will try to capture the sound on my phone.

My differential might need a total rebuild but that is a relatively time consuming service. I will try the easier stuff first.

 

[swathdiver]

Thanks for the help.

I will try adding some friction modifier first to see if it quiets things down. Alternatively, do you think both of my rear wheel bearings could be bad? I've heard that bad wheel bearings typically make a growling noise, note a whine.

My pleasure to help! The friction modifier is for the positraction clutch plates. The noise and conditions you described do not point towards the wheel bearings but rather the spider gears, side gears and or pinions. It could also be the axle splines as well. If you were to change the axle shafts, then by all means change the wheel bearings and seals at that point.

 

[RED TAHOE LS]

Dallas, so many things happen in the rear end, do this, find an area where you get to 50 mph without any traffic, turn off the radio and roll up the windows and cut the engine off and let it coast to a stop on it's own. Write back and tell us what you heard. Axle bearings make entirely different noise than Carrier bearings as well as Pinion Bearings. DON'T TRY TO DO THIS REPAIR YOURSELF, you need a certified garage. Good luck.
David g..............

 

[ivin74]

Your spider gears have to much play