Rear Diff Sound

[garyhugo]

Recently I have noticed a Whirr Whirr Whirr sound from the diff when making a sharp turn at slow speeds. I'm thinking it is the limited slip. Should I be concerned? Changed oil 5 yrs ago, 15000 miles, with Mobil 1 75-90LS. Don't remember the sound back then.

[Mikey]

Did you add the GM 4oz additive bottle?

In slow tight circles it's most likely always going to make some noise.

[conesare2seconds]

Could be worth checking the wheel bearings, unless the sound comes from both sides at the same time. A worn bearing can be noisy on the side that gets loaded when you turn the wheel (right when you turn left and vice versa).

[Mikey]

Another clue will be if the noise is rhythmic with a frequency variation that corresponds to wheel speed. Diff clutch packs tend to be grabby and thus the noise is not so rhythmic. Bad U-joints on the other hand...

[garyhugo]

Did not add the GM bottle of additive because Mobil 1 says it has the additive in it. The rear wheel bearings were replaced oh 25,000 miles ago and so were the u joints. I will get it up in the air and inspect those components. Thanks for the insights.

[Young1]

I had the same thing happen with the mobile LS product. I added 2oz of Amsoil Slip Lock additive and all was well. Saved the other 2 oz for next change.