Has my new PINION BEARING gone bad?

[91Coupe]

I just had my rearend rebuilt in November '03. Parts include Eaton posi, moser 31 splines, and all new bearings. The only used part includes my FRPP 4.10 and the axle bearings.

After maybe 600 miles and about 7 trips down the strip, I noticed a high pitched noise from the rear end. I replaced my U-Joint and the noise is still there. If the car is cold, it takes about a mile for the noise to start and is only heard between 5-40 mph.

Does this sound like the pinion bearing and why would a new bearing go bad. Poor Install??? I ordered all the parts and had them installed locally. The installer said it would cost me another 2-4 hrs of labor ($110-$220) to replace the pinion bearing if it is the problem.

Any suggestions? Does this sound fair?

 

[85 Coupe 5.0]

do you hear the noise when you are accelerating or decelerating? or does it do it all the time after it starts? It's kinda hard to pin down without a little more info. The fact that it is a wine suggests that it could be from improper backlash setting, but the fact that it takes a while to start is kinda weird. does it do it while cornering or in a straight line also? Give me some info and i'll try and help ya.

 

[chevyeater]

check the fluid level first. may not have put enough fluid in on the install. if ok then most likely bad install. gears make sounds like you descibe high pitch or low pitch whines. bearings make grinding or sqeaky noises like brakes do when there bad. some gears will have some whine to them anyway especially lower gears like you have.
Later,
Dave

 

[91Coupe]

The noise occurs all the time. However, if the car has been sitting for a little bit, it takes about 1 mile for it to occur. It makes the noise during straight line, cornering, accelerating and decelerating. The pitch gets higher with speed. It is only heard from 5-40mph.

 

[85 Coupe 5.0]

I agree with Chevy Eater.

I would check the fluid level first. If the fluid level is good, than it's probably do to a poor install. All Ring and Pinion gears make noise, but when installed correctly they don't make noise in the normal range that you would drive in. Example, if set up properly, no noise should occour from 1 to 150 or so MPH, the gears would probably whine about 180 MPH or so, when you won't be able to hear them, i would take it to whoever did it and have them re-check their setting so see if they held.

 

[91Coupe]

Thanks for the support! I went ahead and purchased a new FRPP ring and pinion today. I also ordered a new TA Girdle. I am still debating on where to take my car for the install. I really did not like the attitude from the original installer. Rearends are one of the few things that I have not done and I do not want to experiment with it. Maybe one day I will learn first hand how to properly set up a rear end. My thinking is that the pinion bearing is bad, however, I will not know for sure until it is apart.