Reply to "What oil to run in my ZF gearbox?"

Well, SHOOT!

I just went and found and bought 4 quarts of the Castrol Hypoy 80-90 GL5 that RBT and others suggested, but I was also very interested in the "Shock Proof" medium and heavy Red Line offerings as well.

Just wasn't sure if I wanted to switch to synthetic, or just go with what the old-schoolers suggested.

I found "Brad Penn" 80-90 GL4 too that was also in the running, I know Brad Penn oil is good stuff, at least their engine oils are.

My gearbox shifts as smooth as butter right now. My guess is it probably has the Castrol in it now.

Of course I want to keep it that way, but I do like the idea of running the Red Line Heavy Shock Proof, if it has some advantage over the Castrol or Brad Penn Dino oils. I like the sound of running a heavier weight oil, but I don't know if that would be better or not.


Then there's the Red Line MTL oil as well that has also been suggested.

I still have time, I can return the Castrol, and get any of the other brands discussed here.

Hmmm, decisions, decisions.