Manual Transmission Oil. What's Best?

[glassguy]

I'm close to finishing the auto to manual tranny conversion on my 71 240Z. It's a 5 speed out of a 78 280Z. Since I bought the transmission at a junk yard with no way of knowing it's condition, I took it  to a reputable transmission shop to get it looked at before I put it in. They replaced one bearing and said everything else is good. So, do I fill it with whatever is originally recommened, or have any of you had better luck with anything else. I live in Iowa, so it only gets driven in warm weather and put away in the winter. Thanks.

[SteveJ]

True GL4 oil. Not GL5.

[Zed Head]

The Datsun transmissions seem to do very well with Redline's MT-90 oil.  Better than a generic 90 wt., for sure, with a transmission that has some miles on it.

[cbuczesk]

Pennzoil Synchromesh. You need an oil that works with yellow metals such as Datsun's brass syncros. Redline works too.

 

Chuck

[gundee]

 

Pennzoil Synchromesh. You need an oil that works with yellow metals such as Datsun's brass syncros. Redline works too.

 

Chuck

 

I have also used both of these. Redline currently. I have developed a leak between the engine and gearbox.

Not too bad. I think it is the gearbox. If so I don't think any issue with the oil. My seal is the origional from 1978.

If you do still have your gearbox out I would change the seals anyway.

Edited March 2, 2015 by lumens

[rcb280z]

Yep Redline GL4 75-90. What I have always used.

[Walter Moore]

I have Redline MT-90 in my 5 speed. Penzoil Synchromesh is the only other oil that I know of that is a GL4. Don't use anything else or it will eat your syncros.

(There is sulfur in the GL5 oils and it destroys the bronze synchronizer gears in the transmission.)

[glassguy]

Thanks for all the great advice! I think I'll go with redline. 

[grannyknot]

 It's the NS you need to look for as in Redline 75w/90 NS  (no sulfur)

[beermanpete]

Redline MT-90 or Brad-Penn Multi-purpose Classic. Both are GL-4.

[LeonV]

 It's the NS you need to look for as in Redline 75w/90 NS  (no sulfur)

 

FYI, in Redline-speak NS means "No Slip", i.e. no added friction modifiers (typically used for clutch limited slips). It has nothing to do with sulfur content.

 

Furthermore, the NS stuff is GL-5, not the GL-4 that Z-car transmissions call for.

[grannyknot]

Thanks Leon,  I gotta stop taking forum opinions as facts. I think I'll just go out and drain my tranny right now.