mlopezart

Hey guys, anyone used Amsoil 75w90 on their LS1's for their differentials? Any help would be much appreciated. Thanks!

Marc 85Z28

I've never run the Amsoil 75w-90. Just run whatever name brand you can find. Limited slip additive isn't necessary if you've got the Torsen rear differential, but using it won't hurt.

rv93

i use mobil1 synthetic 75w90. its pretty pricey, but since it lasts so long, it worth it to me

96 Z 28

I run Amsoil Severe Gear 75/90W.

Solved the severe whine in my Diff where I thought the Diff was going to go bad...

I also use their Limited Slip Additive, and it works well.

PS - I WOULD NOT run just any old oil in our Diffs. Our Diffs are pretty fragile due to size as it is, so anything you can do to help out with better oil is going to help.

Preference from what I've seen myself and read, is Amsoil, seems to prevent shear best and maintain it's properties over time much better over time than others.

Gear Lube White Paper from 2007

I'm sure there is some updates since this was done, and Amsoil Haters will come out of the woodwork, but it's not just a ruse. They do make solid products, just not cheap...

EDIT: I also just remembered that they changed the weight specs a while back and some locol folks switched to the 75/110 Weight with more preferring that for it's viscosity ratings

96capricemgr

Please ask for how people are evaluating.

As noted the Torsen does not need limited slip additive because it is not a clutch posi.

Never seen any 7.5" lube failures so IMO all you are going to get is opinions based on marketing.
Don't get me wrong I have seen the Amsoil gear lube test and none of is surprised me.
It IS a marketing piece but it is still worth looking at. Pretty well known Lucas and Royal Purple rely solely on marketing and put out mediocre products and the testing shows that, but even with those I doubt you would see a lube failure.

Marc 85Z28

That's not possible. You cannot quiet gear whine, much less severe gear whine, by changing gear oil brand

The oil used in the axle will do NOTHING to increase the strength of the components, or to reduce the chance of broken parts.

96capricemgr

Maybe the axle was low on oil and getting loud?
Maybe it had the wrong oil entirely in it? I heard a story of someone trying motor oil once and said it was loud.

I agree though, expensive gear oil will not solve a mechanical issue.

Marc 85Z28

That's possible. But again, fluid won't fix that! If you begin to hear noise due to a low fluid level, it's rebuild time!

mlopezart

Wow thanks for the feedback, everyone. I know I have a Torsen diff, and I read I didn't need the limited slip since Amsoil already has it (or my diff doesn't need it), either way I don't think I need that. I'll be getting 75w110 since my diff whine is getting louder. Man its annoying driving on thefreeway, totally demoralizing since I love the car!

96capricemgr

The more you drive it the worse the damage will be.