What type of transmission / rear end oil would you recommend for a 3 speed. I have put in 90 W . I check the oil level last weekend in the trans and it look as it was a bit thin. Should I put in 80W 140 W or is it normal for the oil to be thin. Let me know Thanks Frenchy
I put in all of the oil in the trans. I will do a transmission oil change this weekend and see how thin it will look. Frenchy
90 or 85-140 is fine, It ain't supposed to be like molasses. Modern stuff in the last 20 odd years uses ATF in manual trans, now that's watery.
90W GL4 is what you want for the trans. Most modern gear oils are GL5 and are actually too "slippery" for the brass rings on the synchronizer(s) to get a bite on their mating cones, resulting in gear clash. GL4 is available, but you have to look a little harder to find it. Either GL4 or GL5 is fine in that non hypoid banjo rear. GL5 always in hypoid rears. Someone recommended Lucas additive. If you go to the "Bob is the oil guy" site and find that pic of all the air bubbles that Lucas snake oil entraps in gear lube when it's agitated by rotating gears, you'll never again use that stuff if you've got anything at all between your ears. Dave
Dave I appreciate your help on this I will be looking for the 90W GL4. Thanks to all of you for your feed back. Thanks Frenchy
I will take that as good advice too. Because I work with big trucks, I use advice from extreme duty haulers. 250K lb total weight with a 20 degree drop in trans and diff temps after adding do mean something to me. Temperature drop is from reducing friction, everything else stayed the same. No stones being thrown, just experience. Synthetic in big trucks make a major difference too, FWIW, but most likely not correct for this application.
Amsoil makes a synthetic GL4 that will do a fine job and is intended strictly for manual trans that specify 90W. As a disclosure, I do sell Amsoil as an independent dealer, but I don't push it here on HAMB, I just use it and sell it locally. Dave
The GL-4 isn't a hard and fast requirement. GL-5 contains amine additives that can attack brass/bronze/copper but only when oil temperatures are above 250 degrees -- not likely the case on a car tranny. GL-5 caused some problems with trannies behind Dodge Cummins trucks pulling big 5th wheels, their trannies were steamin' hot.
GL-5 in that application is completely incorrect. New Venture specifies to use 75W90 synthetic. If you don't, you WILL BURN DOWN that transmission. NV4500 and NV5600 use synthetic, nothing else. Back to the 1939 Zephyr correct oil. I didn't mean to cause a derail.
the owners manual sez 90W winter and 140W summer... I'd use the 140W as these old transmissions are quite as tight as the new stuff. The 140 makes 'em quieter, too.
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