What fluid for zf5

[earlybroncoboy]

What fluid you guys running in your zf5's. just put another trans in my truck when i did the clutch job do to a broken ear for the Slave cyl. It is a bear to get in reverse some times it will go in 5 times in a row others just grind or pop out. and 2nd to 3rd grinds in higher rpms. I read that some people put in RP syncromax or red line mtf and it fixes it. Others say only use synthetic atf. I put 4 quarts of Amalie universal synthetic in it. I know being a feramic dual disk might be a bit to ask from the syncros. just wondered what you recommend for fluid.

 

[7.3powerstroke00]

I've had problems with a zf5 grinding and popping out of reverse before, tore it apart and the shift fork was wore down enough it wouldn't lock the synchro all the way in, 5th uses the same fork. I changed out the shift fork and it helped but the synchros were already worn enough it would still grind now an then. I always just put dex4 ATF in them....