Whining Rear end?

So I have a 2011 Mustang GT. It has 91xxx miles as it sits. So I only got the car about 4 months ago and recently I started to hear a howl that seems to be coming from the differential. As far as I know, the car came with a 3.31 and was later switched to a 3.73 Ford Racing ring and pinion. The noise only started happening since it started getting colder (50F) and only does it for the first mile or so on cold mornings. Im hoping its just the fluid taking a bit to warm up but im not sure.

It very well could be the temp change. 3.73’s have always been noisy in these cars also. I’ve had a whine in mine since I bought it 3 years ago and it came with 3.73’s and it now has 65k miles.

Assuming you don’t have a bearing going bad, you can resolve the whine issue with the 3.73 gear sets by tightening up the backlash. I’ve found them to be set at the very high end of spec from the factory. I bought a shim kit and reduced the lash to the min spec limit. No more whine, hot or cold.

DrTriton said:

Assuming you don’t have a bearing going bad, you can resolve the whine issue with the 3.73 gear sets by tightening up the backlash. I’ve found them to be set at the very high end of spec from the factory. I bought a shim kit and reduced the lash to the min spec limit. No more whine, hot or cold.

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Interesting, since there's a pretty good chance my '08 is going to get that particular ratio to go along with a 2.8 bias ratio Torsen for road course duty.


Norm