Hi guys, I changed my zf5 fluid in my 1995 f250 7.3 because I have a bad synchronizer in 2nd so I have to double clutch to go from 3rd to 2nd. I was able to get the truck into 2nd from 3rd at about 5 mph before I changed fluid. I read good things about the redline MTL with people saying that is helped a lot with failing synchros so I decided to try it and now I have to be at a dead stop to get the truck in 2nd gear from 3rd(not double clutching) and now I can't go from 1st to 2nd at all without grinding, and now when ever I go to put the truck into reverse I grind a little. Should I try going with the recommended atf/ mercon 5 to at least get my truck to how it was before or what should I do. Whenever I drained the fluid before changing it, it came out brown. Let me know ur guys experiences with other fluids.

 

Redline MTL is too high in viscosity for your transmission. Use the recommended fluid, Mercon V.

 

I recommend rebuilding the trans to FIX the problem

 

Dump mtl flush with diesel. Fill it with dexatron / mercon you can use Mercon V if you want no real need for high dollar fluid. You can shift these old girls all day long if you learn the art of speed matching up or down. Get good and you can quit using the clutch unless you have to stop..

 

Actually these ZFs call for Synthetic ATF

 

Try Pennzoil syncromesh it is made to go in manual transmissions that use atf, but it makes the syncros grab better than atf does. I use it in my zf6 and the shifting is much better than with the atf I was using.

 

Try plain mercon with a bottle of Lucas

 

I checked my 1989 owners manual all it says is Mercon. Not a word about synthetic. Nothing wrong with synthetic it handles heat better. The biggest thing is to change it at least as often as called for by the owners manual.

 

Diesel ZFs call for synthetic ATF