problem with my 97 3.8 automatic. ive been experiencing this off and onfor about 8 weeks now....occasionally my car will make a roaring noise in the rear end when i accelerate from a dead stop. it only does it on the lashup not when the rpms are up and it is getting ready to change gears. usually by the time the rpms get up to the shift point it has stopped. but then once the car is going and it goes to 2nd gear and the rpms drop it turns into a harsh hum. thenthe processrepeats as the car shifts gears. some people have said it is probably the transmission but i doubt it is because the transmission shifts and feels fine. then my stepdad rode with me and he said he thought it was something in the exhaust system (by the way if this helps any, i have the y87 package, meaning i have duals, and they are stock) sometimes it will do this when ive been driving normally, but most of the time it happens only after a high rpm run (3000+). my theory though is that itseither an axle or rear end problem.help please! thanks!

 

diff could be low on fluild, could be the carrier bearing on the two piece drive shaft, wheel bearing?

 

I am going through almost the same thing, accept that mine has a hum to it all the time above about 35mph. I have serviced the rear end and that did not help. I have an aluminum 1 piece driveshaft on the way and hope that it is the CV on the 2 piece. If not, I will be rebuilding the rear end. I'll keep you informed.

Marc

 

ok cool is yours 3.8 too?

 

Sure is with 180,000 on the odo!

 

It more than likely is your rearend. Its very common on these Camaro. I replaced my rearend last summer, will be putting in a new one this month(better gear ratio.) Fill the diff with Lucus gear oil, its like Monkey snot. It will quiet it down for a while. The way to check this is to get the rear end off the ground. Where the drive shaft meets the rear yolk, see if you can get any movement in and out. There should be a little play, but mine was nasty. It had about 4" of travel it seemed like.

 

really mine has 78500 after sitting in front of my house for 2 years undriven before i got it back running

 

Slow on the update. I replaced the 2 piece driveshaft with the 1 piece aluminum. Good and bad. The HUMMMMMMM went away, but the WRRRRRRRRRR got louder. So, to sumize, the carrier bearing was bad, (the HMMMM), but the rear end you can really here it now, (the WRRRRRRR). Rebuild kit for the rear end will be here the end of the week.

Other bad new is the poor motor I think is on its last leg. Cylinder #4 miss, low power and fuel mileage has dropped from 29 to 23[:'(]This was 4 days after new OEM plugs, MSD wires and coils. Allready swapped back to the stock coils with no change. If I can not figure it out I will be doing the LT1 swap.