Whining noise under a 1984 Vette

[bobb1960]

Just joined this site yesterday and trying to find my way around it. I just purchased a 1984 Corvette 4spd and was wondering if anybody has ever experienced The following problem(not sure if its even a problem. As I am going down the road and let off on the gas there seems to be some sort of whining sound that comes from the car..not sure if its under the car or from the rear. also everytime I left off on the gas the check engine light comes on..when I step on the gas the light goes out and the sound is gone...Thanks

 

[ATL 84]

Welcome to the forum. You will find plenty of help and friendly people.


Not sure what the noise is but if its coming from the center of the undercarriage I would say It may be you clutch. I had that problem once, they put a 87 clutch in my 84 and it is slightly larger.

 

[Notorious]

Whining noise under a 1984 Vette

You don't have one of my ex-wives under there, do you?
It sounds like gear whine from the diff. Your description is very indicative of this. It may or may not be a problem, besides the noise that is. It can be from worn bearings that have allowed an unfavorable wear pattern on the pinion to ring gear contact surfaces. If it's done it for a long time, perhaps it's been repaired but w/o new gears the noise would continue due to the established wear pattern. Not a problem in normal driving, just annoying. However if the noise is new, your bearings could be going away now. Have you checked the oil level, any bad leaks? Generally low oil level is what starts the beginning of the end for differential bearings. If you're not knowledgable on it have a mechanic check gear play, check for excessive movement (up and down) of the pinion and output shafts, and for excessive metal in the oil, etc. A certain amount of "metal dust" would be normal in an older rear and oil that hasn't been changed in many moons if ever. Too much dust or "pieces" spells doom. A good tech or knowledgable hobbyist can help you figure this out.
I don't know what kind of trans. you have, but if it's a manual it could be a bearing in it. But it sounds more like a rear end from what you've described. The good thing is that all '84s had the D36 rear end. These can be picked up for a few hundred at most and installed in a few hours by almost anyone. The D44 differentials go for $1000 or more. These came in the '85 and up manual trans. cars. I just bought a D36 diff for a street rod project for $160 shipped. That was a steal though. Figure on $200-400 depending on ratio.

 

[johnny80]

If you have the Doug Nash 4+3 OD, it will make a bit of a whining sound when going through the first 4 before the OD kicks in. It is common on the 1984-1988 models. If it is the 4 speed, make sure you are keeping the fluid levels up in the OD, it uses Dextron Auto tran fluid. If you can get any type of Repair manual (Haynes etc...) or better, the GM repair manual (Ebay for about 70.00) for the specific year will be a big help. BTW, welcom to the CAC. This site has been a godsend and has saved me thousands in unnecessary repairs and has taught me how to conduct things for myself building my confidence.