I just wanted to make sure, before I did this. I have an 85 GTS, so it has no LSD, and wanted to make sure I'm supposed to use the same oil as everyone recommends for rear diffs with LSDs.

ryanjayx wrote:I just wanted to make sure, before I did this. I have an 85 GTS, so it has no LSD, and wanted to make sure I'm supposed to use the same oil as everyone recommends for rear diffs with LSDs.

Look in the FSM... gear oil specs are listed... without a LSD... I believe (from memory) you just need 90 weight gear oil, around a quart and a half... check the manual to be sure

ryanjayx wrote:I have an 85 GTS, so it has no LSD

LSD was on option for '85 gts'. My car had one from the factory.

Well damn my cars original buyer sucks. I might go pick up a Haynes Manual today. I had one for my DSM, and it sucked. It never told me anything about the 4G63. Mostly about the 420A, and SOMETIMES about the 4G63.

ryanjayx wrote:I just wanted to make sure, before I did this. I have an 85 GTS, so it has no LSD, and wanted to make sure I'm supposed to use the same oil as everyone recommends for rear diffs with LSDs.

Make sure first that it isnt an Lsd cause u want to put the right gear oil in there.The Lsd requires an additve so thats why u need to be sure.

It is almost impossible for you to get the wrong lube for the rear diff, it's GL-4 or GL-5 Hypoid, no additives necessary unless it clutch chatters and only then a minimal amount of the stuff.

allencr wrote:It is almost impossible for you to get the wrong lube for the rear diff, it's GL-4 or GL-5 Hypoid, no additives necessary unless it clutch chatters and only then a minimal amount of the stuff.

Its not that impossible if he really doesnt know what he's looking for.For example,last time i went to the parts store the guy looked up what gear oil is used for an 85 GT-S and he said it was 85w-140.I didint remember exactly which one it was but from previously buying this i knew it wasnt that one.If i was a first time buyer on this i would have bought the wrong stuff so its really not that impossible.Also,I have always heard that the additive should always be added to avoid the chatter or damage to the Lsd.Plz correct me if i am wrong as we r all here to learn.

Thank u....

^^^"Friction modifier"? I would say it improves the lsd's overall function & it does help eliminate clutch chatter, differientation in cornering & such, but this only applies to a new or good diff...as opposed to a worn out unit with bad clutches, the additive would otherwise be useless

75-90 or 80-90 gl-4 or gl5

Thanks for the info guys.

With the factory LSD or non-LSD rear end you can use just about any 75w90 or 80w90. Some of us drift guys or dudes in the desert run 80w140. It's a little thicker for the hotter temps. It's just a viscosity. Acts like a 80 cold, acts like a 140 hot.

For an aftermarket LSD or one that chatters I would recommend:
-Redline 80w90
-Torco 80w90 Synthetic
-Torco 80w140 High Shockload iirc?
-Motul if you got your F1 shoes on reading this