Ok, so first i have a 99 camaro 3.8 V6, 90 000 miles

Ihave been to 3 different mechanics for the same grinding sound from rear passenger side more tilted to the middle of the car. i have 3 different answers, i tried with one of the answers and it was that my shocks were old and i had bad tires(wavy thread wear) so i just spent 1000 bucks to get new shocks and tires for the car and the second i sit behind the steering wheel i hear the grinding sound, by the way i just changed the bearings like 1 month ago(could it be that they are installed the wrond way?). So i'm out of money soon and i wonder what can my problem be? the mechanics obviously dont know what they are doing or its just the fact that they are trying to rip me of my money..............[:@]so is the problem the bearings, the differential, the shocks, the tires, the axle.....?(that's what i have heared from the 3 different autoshops)


Iappeciate any help that i can get.....

 

You need a new rearend dude....I have the same car and the rear end was junk. I swapped it from a Z28. Easy job. The ring and pinion are junk. Its common in these cars. I bet if you pulled off your rear dif cove, your gear fluid would look like silver paint.

 

Okay $6 fix (probably around $25-$30 if you have a limited slip diffenential.) Change your differential fluid with a high weight conventional oil. I like Lucas 85w135, and if you have LSD put in two bottles of the GM LSD additive instead of just one. That will most likely fix your problem.

 

So, Chappie99 did your car have a grinding sound too? how much did the swap cost ya? what is a good price?

 

hmm sounds cheaper than getting a new rear end, is it easy to change the diff fluid? could i do it myself, by the way i'm a rookie....what do you think about the other answer that i need to change the rearend? by the way if one mechanic misled me and said that i need to change tires and shocks but it actually was the differential...what would u guys do? like go back and complain or somethin? (not only rookie, new to this country too )

tnx for the reply

 

You said you replaced the wheel bearings. Were they definitely bad, and was the noise there before you changed bearings? The Camaro is a good handling car, and driving it like a slot car around turns has a tendencyof wearing out the wheel bearings sooner. The worn bearings puts undue stress on the ring & pinion gears, causing a gear mis-match,premature gear wear, and a possible whine. I had a 96 z28 that whined, and it also gave a slight clunk/knock once in a while after backing off the throttle (not your normal back-lash type of clunk). Although the limited slip diff came in a little over 12% of the 3.8 models made, it's possible you have one. Old, bad diff. fluid will cause the rearend to chatter and make a rhythmic clunking,while making a turn. If you have a limited slip, and that is what you are experiencing, then I too wouldrecommend changing the fluid and additive first as Banks described.

 

This is from my post in the "Need Info On Fluids" post in the "4th gen," "V6" category.

Differential fluid- 85w90

If you have a Limited Slip Differential then you need the GM additive from the Chevy dealer. I think you only need one 2oz bottle, but if your rear end is making noise then it would be best to use a higher weight like 85w140 and two bottles of the additive. I changed my differential fluid the other weekend, and used about a bottle and a half of Lucas 85w140 which comes in 32oz bottles. This fluid change is very simple, and also requires a pump to pump out the old fluid. There is no need to take off the differential cover, and there is a plug on the top on the differential on the passenger side of the car. Just pump out the old fluid and pump in the new. Also be sure to use PTFE Thread Seal Tape on the threading of the plug before you put it back on. I reccommend using conventional differential oil solely due to the application that it isn't metal on metal contact such as the engine.

It's worth the shot to at least change the diferential fluid, if not then you're only out a few bucks. As for those shister mechanics I would at least complain that they misdiagnosed and therefore didn't fix what was wrong with your car. Since its kinda hard to prove that there was a noise before you took it in its basically your word against theirs. I'm not sure if you will be able to get your money back, but just don't go back to those places and don't reccomend them to anyone.

 

Ya it was grinding like hell. There was about two inches of travel in the rear yolk. I pulled the rearend from a car in a bone yard. It cost me $250. But time and everything else is another thing. The only reason I changed mine was cause there was so much play in the rearend and the front pinion seal was leaking so bad. It def, needed a swap. The only possitive was I replaced it with a posi rearend. If you do change the rearend, make sure if you have the option to choose, make it a reaerend from a car with an auto trans, less abuse.

 

Well the only problem is that i dont only hear the sound when i am turning but i hear it all the time, when i am on the throttle its fine and i dont hear anything but the great sound of the engine(first american car love it) but when i get off the throttle i can hear the whining and grinding...so the question isshould i only hear the sound when i'm taking a turn or even on a strght road? the sound was there before the bearings job, theautoshop said that the problem was the bearings at first so i changed those....but that didnt solve my problem...i'ma got fot the cheap way and see if it helps, by the way tnx for helpin me out..

 

Sounds good, cheap and effective so i'll try it but what sort of pump do i need and where is a good place i can do the change (sorry not from here so dont know much) like any "do it urself places" or should i just find a good spot at a parking lot?

Also be sure to use PTFE Thread Seal Tape on the threading of the plug before you put it back on. I reccommend using conventional differential oil solely due to the application that it isn't metal on metal contact such as the engine.

ok so i dont really understad this part what is PTFE and i assume that the plug is the one that i take out to pump the fuel out of the system, and i also asume that i should pump in the fuel in the ame place i took the plug out right? heading the right way?