Oil for S III transmission

[Craig Broadhurst]

I am in the process of finishing putting a SIII transmission in my SII A 109. I read somewhere about how certain oils corrode the brass synchro parts. Anybody have advice on which type of oil to use? I was going to use some GL 4 90 wt.

Thanks,

Craig Broadhurst

[DblD]

Craig,
I run regular 90-weight gear lube. I purchase it at the local tractor supply store by the gallon(s). It’s a less expensive than at the auto parts store. I can’t speak for long-term effects, but I have been running this since 98 with no ill effects – knock on wood.

David
’71 - SIIA Ex MoD 109

[Bogatyr]

Craig,
Yep, any GL3 (if you can find it) or GL4 rated 90wt should be fine. GL5 is the stuff that is supposed to corrode the soft metal bits. If you want to get fancy, RedLine MT90 is good stuff and GL4 rated.

Bogatyr

[Esha]

Speaking of what oil to use, what do you suggest for cold climates?

Esha

[Bogatyr]

Esha,
I live in upstate NY, while certainly not AK, we do get our share of cold up here. I've been using RedLine MTL in the Hondas/Toyotas we have for quite a few years, mainly because of the cold weather performance. Now, the Rover takes MT90 and that seems fine too, although I don't drive the truck much in winter since it's a soft top with no heater.

I currently have 85w140 in the diffs as they were really loud, I wouldn't recommend that in cold climes. There are also a number of variables here, do you have a garage? Any leakage? How is the performance of what you have in there?

If the vehicle is new to you, I'd suggest changing all the fluids out anyway, unless you know it was done recently. You can always start with whatever is cheap and available and see how that works for you. If the performance is bad, step up to something better...

One thing I'll remember, there was a Peter Egan article a while back in Road and Track where he was wondering if he would ever live to see the advantage of the 7$ a quart oil he was using...food for thought...

Bogatyr