The Stovebolt Site Forums The Shop Area Engine Shop Trans 80-90 Gear oil

After reading the post about DOT 5 brake fluid , it reminded me of something I go involved with. When you change your trans oil make sure it does not have GL-5 in it. It seems that API GL-5 is not compatible with "yellow metals" such as synchronizers and other bronze trans components. Forced to do some research on this, I found GL-4 is ok to use. Pennzoil Gearplus 80-90 with GL-4 is about the best choice IMHO. Just one more thing to watch out for.

Good stuf to know, If my 4 spd. had synchronizers I'd be worried

Kip's41,

I wonder if your transmission has countergears that run on bronze bushings, most do. This would fall under the category of a "yellow metal".

I have heard it takes many many moons before the sulphur or whatever additive it is that reacts with the brass/bronze to do any harm, and then it's slight.

Stuart

Good point. Just checked the shop manual and according to that the counter shaft runs in Hyatt roller bearings. However there is something wrong in there as the trans. howls something terrible. I’m just beginning to pull it out to rebuild. I’ll know shortly and be sure to refill with GL-4.

Just curious....checking the jugs of gear oil I have in the shop has them all listing GL-5, GL-4, GL-3 applications which I run in my 1985 NWC T5. I've only got about 3k since installation, changed it out after 1K, filtered the oil to see if I could detect any metal (couldn't) and the transmission shifts like butter and is quiet. There was some question as to whether Dextron should be used in the NWC transmissions...I chose to go with some advice from a box builder, but he didn't mention the GL-4 info. You mentioned the Pennzoil Gear Plus 80-90....did you find any other manufacturer brands that you might recommend? Is the Pennzoil available in most FLAPS? If it's readily available, I might just drain and filter again and transition to the GL-4. Thanks for the info.

Dave

Around here it's available at the tractor supply stores in 5 gal or some call it 35 lb pails . Could not get an answer from my Napa guy, except he would look into it.
The Pennzoil part #'s are
Qt - 21176
35lb/5 gal pail - 4804

Thanks,

Dave

Just an update. My Napa guy got back to me on the use of Napa/Valvoline/Ashland 80-90 gear oil in Stovebolt trans and rears. Even though Napa specs say GL-4,GL-5, their product will NOT harm "Yellow Metals" such as synchronizers and bronze bushings. The part # for a 35 lb/5 gal pail is Napa 75-213.

An update on my comment above. Now that the transmission is apart I see that the counter shaft does run on roller bearings, BUT the reverse idler gears run on two bronze bushings. So I do need a lube that is friendly to yellow metal.