5 speed transmission grease

I am going to go with the engineers who designed the transmission over the guys who rebuilt a good transmission on this one and tell you to stick with what the manual tells you.

Mine says 75W90 API GL5 too. Others in this newsgroup have said that there are problems with GL5, because of sulfur. I don't know about that, but it would be a mistake to put 10W30 in this transmission. It doesn't have the "shear strength" that 75W90 does. Shear strength refers to the ability of a lubricant to prevent direct metal-to-metal contact of lubricated parts. Gears, shafts and bearings are all designed to ride on a film of gentle, cushioning oil, not on each other.

Off the counter 75W90 lubricants will sometimes have limited slip additive in them. This would bad for the synchromesh clutches in your transmission. Jerry is going to take issue, but I have had good luck with Mobil 1 75W90 synthetic gear oil. Other people recommend Redline Manual Transmission Fluid. Using the cheapest off the shelf formulation is false economy here, considering what the transmission cost you.

Earle

Hmmm, sounds like they have been working on too many vintage Honda manual transmissions. :-)

I would do the 75-90 gear oil but not the GL5. I use Redline 75-90 GL4 I think and that is friendly to the syncros.

Good Luck...

BTW what kind of wallet damage to have your 5 speed tranny rebuilt? I am assuming it's an AX-15.

I am embrassed to say - 1500. As far as the type of transmission, all I know is that it is a 5 speed standard and the car is a two wheel drive. I think I got taken. The real problem was that the right side motor mount bracket broke causing the engine and transmission to be tilted to the right. As a result, I could not shift into 5th or reverse. There was a lot of vibration that I thought was coming from the transmission. The guy at the shop said it was the catalytic converter. I should have known better. I never even looked at it until I put it on the rack at another shop to check the converter. That's when I noticed that something was wrong with the mount. How they even got the transmission out of the car and back in is beyond me. I went back to the shop and asked them how they missed the mount problem and they just stared at me. I think that the angle of engine and trans keep me from being able to shift into 5th . After fixing the mount problem, it was almost impossible to shift into 1st and 2nd. I usually won't do something like that without looking at the situation, but it had been a bad week already, and my wife was hollering to do something about her car so it did. Well the old saying, act in haste, repent at leisure was sure true in my case. Where might I find the Redline transmission grease. I have never seen that brand. Thanks for the info and for my chance to vent.

You need to talk to a lawyer.

Earle

Two things... 10W-30 motor oil is very close in viscosity to 75W-90 gear lube so they weren't all that far off... even though it wasn't exactly the correct "stuff". But your AX-15 transmission requires a GL-3 75W-90 so that's what I'd use. Redline MT-90 is about the best direct replacement any of us have ever found which is available at either

or Some early manuals said GL-5 75W-90 but GL-5 was a typo... GL-3 (or GL-4) is what you want as GL-5 has some sulphur-based additives that are hard on the gear synchronizers.

Jerry

milt> I recently had my 5 speed transmission rebuilt (unnecessarily, but that is a

10W30 may have similar viscosity to some synthetic gear lubes, but it does not have nearly the shear strength.

On the second link, scroll down to where it describes "Boundary Lubrication". This should give you a good picture of what will happen when you try to use motor oil in a gear lube application.

Earle