Too Slow '90

Couldn't find the Amsoil gear lube locally so I picked up Mobil 1 Synthetic Gear Lubricant LS and then went to the dealership for the additive. They said it did not need the additive because it is already in the Mobil 1. On the bottle "Limited Slip Friction Modifier Included" is written. Do I still need the additive or am I using the incorrect gear lube?

I also read a post here where it advised not to use synthetic because it could cause leakage. Is this a concern?

Thanks in advance as this is my first Rodeo with a ZR1.

Dynomite

I use Mobile 1 Synthetic Gear Lube LS with no additional additive and no issues.
LT5/ZR-1 Fluids

Paul Workman

One example does NOT a trend make, but far as leaking goes...no issues here (using Redline synthetic per Marc Haibeck's suggestion, and no complaints w/ M1 either).

Dynomite has in his archive a method of installing a drain plug in the differential housing. If you haven't already installed one, you'll wish you had! It takes maybe 5 minutes to drill/tap/install one, once the car is lifted enough to get to the diff'.

Welcome to the Brotherhood of the Beast!

Link to the ZR-1 Registry club

WVZR-1

The service I don't believe is required often enough to justify the potential aggravation of an installation failure.

The GM LS additive ain't that expensive and ain't going to "kill" the properties of the "whatever choice". The composition of the friction plates has changed through the years and while most mention "no issues" some certainly have.

** The GM/ACD LS additive has changed through the years also. When I first started using the additive we used it for everything from "noisy rockers" on GM 235 CI to the differentials. It's original formulation I'm quite confident was from whale oils.

Toss the coin? Maybe. Would miles maybe be a game changer? Maybe

It's certainly an easier add "before" than "after" if yours maybe had an issue!!

Amsoil doesn't say "NOT TO" No where in the Amsoil guide do they say "NO"


The link may not stick for a '90 Corvette but I'd think the guide will stick and use the drop-downs.

http://www.amsoil.com/mygarage/vehic...LET+CORVETTE+J

Even Amsoil suggests LS additive if you experience "chatter". Why wait?

http://www.amsoil.com/shop/by-produc...-oil-additive/

Dynomite

Regarding the Differential Drain Plug Installation............It is easier to install the Differential Drain Plug than to try and suck out all the old Differential Fluid. So.....why not Install the Differential Drain Plug and once and for all get all the old fluid drained out.

As you like with the Differential Drain plug removed (after the hole is drilled and threaded) you can flush out the system by installing some New Fluid in the Differential Fill.....and make sure you can remove that Differential Fill Plug before you remove any Old Differential Fluid.

See Item #4 LT5 Added Systems