Fluid change - recommendations

[Dave Rifkin]

I have a 1969 L46 Corvette that I have been told should have the rear end fluid changed. I recall seeing, on this forum or one of the Corvette forums I frequent, where the guys suggested using Ford's friction modifier when I change the gear oil. Is that something this group would suggest over a GM product (or any other manufacturer).

I was wondering if I should change the manual transmission gear oil while I am at it and was hoping to get some product suggestions or tips from the guys on this forum.

Ultimately I would love to get a list of recommended products to use when changing the rear gear oil, transmission gear oil as well as antifreeze (while I am at it)

One more question; for a car such as mine that doesn't see that much use should I stick with conventional oil in the engine or is synthetic recommended?

Thanks

[Dicky]

Dave, I can give you my thoughts on gear lube.
Make sure its GL4 only, not GL4-Gl5.

Seems everything other than GL4 has Chlorine in it,
and eats yellow metal (copper, brass etc.) synchronizers and such.
some possible brass washers in rear ends. This of course applies
mostly to cars of this vintage.
GM P/N 89021671 Additive P/N 88900330 Most Chev. dealers will get it.

I use a Brad Penn GL4 lube in tranny & rear end with the GM additive in RE.

[69 Post Sedan]

My transmission builder wanted me to use Sta-Lube GL-4 gear oil for my Muncie.

Sta-Lube GL-4

The place that installed the 4.56 gears told me to use Motorcraft Friction Modifier.

Motorcraft Friction Modifier

Kurt

[Donnie]

why not go to the Chevy dealer and get GM gear lube and posi additive? been using it for 30 years with no issues.

[earntaz]

X2!!!