I just had my 3:73 gears installed and they are a little noisy. Can I use Luscas 80W90 gear oil in them to quiet them down some. I didn't have any friction modifier in with the oil b/c I had a 10 bolt cover with studs on the way. Just wondering if anyone else had used it and if it worked. Thanks.

 

i got lucas in mine...the heaviest they had on the shelf....i forget the numbers...maybe 80/140 or something like that

 

I've always used a Valveline synthetic that already has the Posi-Lock in it. It's not cheap though, something like $15 a bottle.