I have had a constant humming sound from the back of the car for a while. I do not know if it is normal or not. I am driving a 6 spd and will get it in high gears when i accelerate. I think it might be from the differencial does any one have some insight on this?

 

I had mine start to whine this weekend. I caught it just as it started and drove maybe 5 miles on it with the noise.

I went ahead and changed the rear lube. I had some typical small filings which I would have expected with a car that has not had its rear oil changed for 50K miles. Gears looked very good with consistent wear pattern.

Pretty cool, as I used Mobile 1 synthetic and they suggest you don't need diff. additive if you use it (right out of the Firehawk manual). No more noise.

More than likely I will have to do some bearing replacement sometime in the near future. As for now, noise gone.

Ben

 

try changing the rear end fluid. if you run synthetic, i would use the limited slip additive. however, you may have to drain your fluid after a few hundred miles if you are putting synthetic in for the first time. the synthetic cleans the differential out pretty good. the gm limited slip additive is recommended over other brands. this stuff is actually a friction modifier. i believe its for the clutch or posi unit. i would not run without it.