Hey my 99 corvette makes a grinding sound coming from the rear, I think it is the posy traction because it happens when I turn. I just had the fluid changed in the diff and I added the posy lubrication additive, and it still makes the noise, im out of ideas, can any help.

 

I've read on here something about this and I believe that the guys came to the conclusion that it was the wheel bearings making the noise while turning. Someone will chime in soon....bob.

 

Did you make the figure 8 turns after you put in the posi fluid? You need to do a bunch of these to get the posi fluid worked into the posi clutches.

 

Get the car up in the air, and see if you can isolate the noise to a side.

 

lots of things to observe when they're up in the air!

 

ill try the figure 8s hopefully it works

 

Well, you can try the figure 8's, but I would not move that car until I figured out where the grinding noise is coming from......

 

With Lucky ,i would try to get it in the air ,a rack & see if i can hear or see anything ,or if u are brave,i had something similar happen ,kept hearing noises from the rear/Bad Vibration,ijacked the car up in the rear ,rear is on 2 jack stands with the jack still under neath it ,& started to spin the tires over to see if theres anything showing itself /I actually cranked my car & put it in gear & gave it a little gas i advise not to do this ,,if it is a bearing ,it maybe /Not saying it is ,in the boot & u wont be able to see it ,There are boot repair kits , If u feel like u wanna to tackle this job, ,The dealer also sells this boot with the clamps ,try to cut the boot clamps off to see if u can see anything out of the ordinaryu may or may not see anything ,or take it to a competent mechanic who knows what he is doing & be prepared to pay him his wage , does it make this noise in straight line driving also ? My Vibration was coming from the lugnuts on the drivers rear tire not tightend,all lug nuts were loose & i was able to turn by hand ,talk about a nightmare/Wrck waiting to happen ,i was able to tighten them all to 100 ftlbs of tq & the vibe went away If u are gonna take off the boot & replace a bearing or bearings ,i would get the manual on your car ,theres great detail in this & wouldnt try to tackle this job without the manual ,gl ,hope u get it figured out soon

 

the diff in my 2000 coupe was making a grinding sound a low speed, ofter backing up.

My favorite Chevy serv mgr suggest I install 2 bottles of the super special GM posi-traction lube when I changed the syn gear lube.

He said in his experience the diff likes to be changed frequently.

I changed diff gear lube [synthetic] at 25k.

Did so....and no further sounds.

hope this helps.

 

it only does it when I turn the wheel, I hear it most when I back up slowly in my driveway

 

I got the grinding sound when I back up lately. Then today, when I was just making a turn while going forward at low speed I heard it. YIKES! I've only recently had the posi fluid changed and the posi lube added and did the figure 8's. That was a few weeks and a couple of thousand miles back. No problems until these last 2 days. HELP. Any ideas....

Padrino

 

Turned out to be my bearing hub on the right rear. Getting both left and right done while the mech's in there putting on the shocks/sways/etc. At least the problem was found when I wasn't out in the middle of no where! <that's my guardian angel!

Padrino