Happy Holidays everyone, ok was hoping to get some info on a recent issue that developed with my differential. The car is a 1995 Camaro Z28 6 speed and a couple of weeks ago everything was fine until I decided to replace the differential fluid. Used quality mobil one gear oil and off the shelf LSD additive.
Right after the gear oil change the diff developed a whirring sound above 20mph which becomes deafening at higher speeds. After that I changed the gear oil twice, this time using a GM friction modifier and increasing the oil weight each time to no avail.
I’m assuming a rebuild is in order but still would like to get a handle on any similar issues anyone has had and how you solved it. What’s odd to me is before the gear oil change the diff was quiet.

 

what oil did you use? 80/90

 

Are you sure it's filled? My Jeep leaks diff fluid and when it gets low it'll make a whirling noise letting me know I gotta add some to it.

 

It reads like the damage is done. No lube is gonna stop noise now - something is out of spec and contact is not smooth. I will bet if u take it to the local driveline shop they will say rebuild but they want your business and $$$.

Hey these 7.625" 10 bolt rear ends are plenty and cheap. Rather than $1000 rebuild find a good used from the local boneyard for $300-$500 and swap it yourself. I see 4th gen rears ends on craigs list everytime i look too - $200 maybe if u come a get it.

Good luck.