Best oil for Muncie M20

[gtc]

Okay you Muncie transmission owners, what oil do you use?

I'm told some people use 20W50 engine oil, but I'm a bit leery of that.

I've read some warnings against using GL5 spec oils as they have additives which are not friendly to the brass synchros, so I'm wondering which brand of GL4 oil to use.

[Chromie]

Hi gtc;ay
The factory book says multi-purpose gear oil
I use 85W90 gear oil and have never had any problems
Or you can use
DuraGear for manual gearboxes that have notchie syncro's;-)
How is your clutch going:}

[MADVET]

Originally posted by gtc


I'm told some people use 20W50 engine oil, but I'm a bit leery of that.

Don't do this, engine oil is way to thin for gearbox use.
As Chromie says use a decent 85w90 gear oil.
 If you give your gearbox a bit of a hard time and don't mind spending a few extra bucks* i recomend "REDLINE Lightweight Shockproof gear oil". It's all synthetic and is 75w140. It was recommended to me by my local Trans workshop.






*Ok maybe more than a few extra bucks;39