What Lubricant is Used in The Final Drive (Differential)?

[Otto Skorzeny]

Owner's Manual and Factory Service Manual both specifically state NOT to use conventional differential fluid (I'm assuming they're referring to 90 weight or heavier gear oil).

They recommend using their own special proprietary brew called "Oldsmobile Special Lubricant, Part No. 1050015. Sounds exciting.

Anyway, what is that stuff and what equivalent product can you buy today? Also, where exactly is the plug located for checking this?

[Otto Skorzeny]

Probably doesn't matter but this is a 1966 Deluxe.

[Otto Skorzeny]

So no one on this site has ever had to add oil to the differential on a '66 Toro?

[bluecab]

Mine is empty as it is laying on the floor in my garage, but I seem to remember that the requirement was to use the same oil that went in positraction rear ends.

[Otto Skorzeny]

Mine is empty as it is laying on the floor in my garage, but I seem to remember that the requirement was to use the same oil that went in positraction rear ends.

Which is.....?

[Doc Hubler]

I have to go back and see if the 67 manual says anything more specific. I also need to know this soon as my final drive has bee apart and is ready for reassembly now.

[xgecko]

I used a modern synthetic gear lube 75W-90 weight. It should work well and last indefinitely. I know there are differences in the early year (Planetary vs. a more traditional design) but I doubt it matters. Keep in mind the performance of modern synthetics is far higher than that of the fluids they had available.

http://www.oreillyauto.com/site/c/detail/VAL2/975/N2365.oap?ck=Search_N2365_-1_2538&pt=N2365&ppt=C1985

[Otto Skorzeny]

I agree that synthetics are superior in some cases but when the manual specifically says NOT to use something I don't want to take chances. The standard diff back then would have taken the 75-90 gear oil but Olds says no dice on the Toro.

We need to know what was required and what the difference was between it and the regular stuff.

For all I know they want you to use 30 weight in there.

[xgecko]

I am not so sure it is that critical today. It is a planetary gear, so it wants a slightly thinner viscosity.

Here is a discussion that largely confirms my recommendation:

http://www.hotrodders.com/forum/66-olds-toronado-139383.html

I also spoke with Vic at AppliedGMC and he also felt that this gear lube will work well for you. Keep in mind modern lubes are far more versatile than what they had back in the 60s. Sure, sometimes the requirements do change as we know from ATF and Engine Oil formulations, but gear oil is for the most part gear oil even today.

[Schurkey]

http://www.bobistheoilguy.com/forums/ub ... 136&page=1

Also found from another source that the original lube was superseded by GM P/N 1050081, which is a positraction-fortified gear lube.

Rumor has it that these "special" differential fluids were whale-oil based, just like the early ATF.