Royal Purple 75w140, 92K, 12 Jeep Wrangler Unlimited Manual Trans

[TXHunter]

Drained and filled with Amsoil MTF. With the thick gear oil 2nd hated shifting when it was cold out, way smoother with the lighter Amsoil fluid. The RP was installed before we bought it so we decided to run it and not change early, but probably worked much better in South Texas where it came from. Up here in North Texas I think it's a little too cold for something that heavy.

 

[Greasymechtech]

Who put 75w140 in a manual transmission? and a GL5 to boot? why oh why?

There is one thing bumping up the visc a little for weather or engine power changes, but a 140 grade... nuts. I would've removed it instantly.

It takes a syncroshift, synchromax, synchromesh, MTL/MTF fluid... Even with power mods and temp, I probably wouldn't go over a 75w85 GL4 and would never put a GL5 in a civilian manual transmission.

BTW, ~110 ppm wear for ~30k+ miles is nothing to worry about.