[6speedTi]

Here is a good informational link.

M20 & M32 Gearbox: Chocolate Bearings - Still Running Strong

The ULTIMATE GUIDE to the infamous M32 gearbox. Learn everything about bearing failures in the M32 and M20 gearboxes - Causes, Symptoms & Repairs.

stillrunningstrong.com

The above gear oil is what the manual calls for. GL4 75w85 which is what I used. Unfortunately the price has jumped up dramatically. I paid $62 in 2021. Now it's $90 and higher. 😡

 

[Banzai]

Thanks a lot! This article is very helpful!

 

[Barry Allen]

Any good synthetic Diesel engine oil would meet GL-4 specs if they tested it for such.

Shell Rotella engine oil is probably easily available anywhere near you.

 

[Barry Allen]

https://a.co/d/feuyiE4

 

[6speedTi]

Any good synthetic Diesel engine oil would meet GL-4 specs if they tested it for such.

Shell Rotella engine oil is probably easily available anywhere near you.

Engine oil in the gearbox?

 

[Barry Allen]

Engine oil in the gearbox?

Yes. Most Diesel engine oils would meet the specs for GL-4 if they were tested as such. You can find synchromesh transmission fluids and when analyzed they are basically 5W-30 Diesel engine oils with some friction modifiers added. The viscosity is close to ATF. If they were tested, they could be classified as GL-4 oils.

You absolutely want to stay away from GL-5 oils. Even if the bottle says it is GL-4 compatible, it's not suitable for synchromesh transmissions. If the bottle says GL-5 anywhere on it, DO NOT USE IT in a GL-4 application (in a manual transmission).

 

[Barry Allen]

Yikes, I just noticed the original poster is in Belarus. Maybe Shell Rotella oil isn't widely available near them.

GL-4 gear lube is an absolute requirement for long life of the synchros in the manual gearboxes. GL-5 oils will wear them out prematurely.