Hi Dave: Another question. I have a 2007 Cadillac STS. I had the differential changed twice because of a humming noise. Now its off warranty I took it back to the dealer and said they cant find anything. Its like a moaning sound between say 60 mph and 65 Mph. No change to performance, etc, etc. its a little annoying, but the dealer sez, there is nothing wrong. I have to believe them. The performance of the car is good and has 144km on it . Your thouhgts??
Hello and thank you for trusting me with your question. My name is XXXXX XXXXX X will do my best to help you with your Cadillac problem.Is your Cadillac and all wheel drive model or rear wheel drive?
Rear Wheel. Just so you know, its a moaning sound. More annoying than anything else.
Does it seem to change when accelerating vs. decelerating or coasting?
No not at all. Just between say 60 MPH and 65MPH thats it. it doesnt get better or worse, coasting, declerating accelerating doesnt make a difference
It is likely just a little gear whine then. Since it does not change whether loaded or unloaded, I do not feel that you have any bearing failure occurring in the differential. Sometimes changing the lubricant can have a positive effect on noise levels. The car already uses a synthetic lubricant so it should be fairly quiet, but sometimes changing brands will help. You can try a synthetic gear lube from Amsoil or Royal Purple to see if this will help. No guarantees and these synthetic lubes can be expensive so it is a bit of a gamble.
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