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ZF5 fluid? What's best to run?

3.4K views 3 replies 3 participants last post by  Got Smoke?  
#1 ·
I had my ZF5 gone through about 3 years ago. I was told by the shop who did it to run regular ATF in it, and change the fluid once a year. So I have

The first year it was perfect, the second year, when it was cold out it was a bit stiffer on a 2-3 shift, and this year the 2-3 is a bit worse than last year again.

Was thinking if going to a red line or royal purple ATF might help this? Seems worse in cold weather for sure.. Was perfect all summer.

Or is there another type or brand of fluid I should try.

If this does not help I will probably send the tranny back in to be gone through next fall and change the clutch as it will be 5 years old.

Thanks so much!
Bob
 
#3 ·
I run mobil 1 synthetic in my ZF6.... no way would I be changing every year tho unless pulling heavy and LOTS of miles

I actually kinda wondered if regular atf would let the syncros get a little more grip and make it shift easier..... it shifts quick n easy at low rpm's but wind it out and shifts take a while
 
#4 ·
I'm having good luck with Amsoil Signature Series Multi Vehicle ATF (red label/cap) have about 25,000 on it since August of last year hauling hot shot with a 43' 3 car trailer. Amsoil says it can go twice your manufacturer's severe service recommendation, but I'm about to change it again since I work my truck more than most.