What oil are you running in your ZF6 + Xcase

[builtnotbought]

My truck is due for a complete oil change, i was thinking about switching to Synthetic 75W90 In my tranny, Xcase and differentials. Anybody else using that oil, if not what are you using

[timmyboy76]

i got a 2wd 6sp, and supposedly, your to run ATF fluid. I recently changed mine out, with Amsoil synthetic...6qts.

[builtnotbought]

That is what the book is calling for, i guess i should go with ATF, I was just thinking maybe somebody went with 75w90 or something else and had good luck with it.

[Wayne64SS]

definitely needs to be an ATF. I put just reg valvoline Merc V spec ATF in and i don't really like it. I'm going to switch to Royal Purple or GM ATS-295 spec ATF. That's what the chevy boys are running, and their fluid is more critical because they don't have coolers like our badass Fords do.

[builtnotbought]

[whitelightning150]

NO our transmissions dont take gear oil they take ATF. i know it sounds stupid but i checked a bunch of different sources before i changed mine. i wanna say that i just put standard MerconV in my tranny. if you dont believe me take the fill plug out of either one and smell it. gear oil smells like sulfur like im sure you know.