Diff whine
Thread Starter
Le Mans Master
Joined: Oct 2008
Posts: 8,877
Likes: 980
From: Whitby Ont.
Diff whine
Picked this 02 Z up in feb of this year, has some work done to it, nothing exotic, has RPM trans and diff in it, i am hearing a trans or diff whine under light load, put it under load, seems to go away, under light load, is when it appears. I am 99% sure is the diff. I have changed the fluid with Royal Purlple plus a modifier, as per RPM instructions via email.
Am wondering if anyone else as incurred this obnoxious whine with the RPM diff. with the 390 gears. Some say is standard, some say shouldn t be there. Not sure i want to take it apart this winter or not.
Am wondering if anyone else as incurred this obnoxious whine with the RPM diff. with the 390 gears. Some say is standard, some say shouldn t be there. Not sure i want to take it apart this winter or not.
Instructor
Joined: Jul 2016
Posts: 207
Likes: 23
From: Atlanta, Ga
My 02 Z whines exactly same as yours does. I just turn up the radio more so I don’t hear it. My train of thought on mine is, yeah it might last another 10,000 miles or it might only last 10 miles. I just changed the oil in mine and put Amsoil severe gear 80w90 along with the modifier. I’m gonna drive it at least till the noise gets louder or it starts making different noises. GM really must have saved a lot of money putting these cheap no good for nothing rear diffs in our cars.
Instructor
Joined: Jul 2016
Posts: 207
Likes: 23
From: Atlanta, Ga
I’m wondering what the root cause of C5 rear diff whine is? Was it not assembled and set up properly? I highly doubt it considering RPM assembled and set it up. Was the new 3.90 gears not broken in properly for the certain amount of miles keeping the speed under a specific mph. That’s very very likely. Or was it just abused by the previous owner? That’s a possibility. All I know is that I had a 2000 Z28 Camaro with the stock gears in it that I ran the ever living snot out of that car. Kept all the fluids changed out on a regular basis. Ended up selling the car and it had 235,000 miles on it. I know I’m comparing apples to oranges here and that the rear diffs are totally different on the F body Camaro and the corvette. It’s not a secret the rear diffs are the weakest link on the C5 especially the Z06’s. The rear diffs on the F body’s have such a small weak 7.5” ring gear and the still seem to hold up better than a C5 vette does. Just stating my opinion here.
