I have an np435 in my 79 f250. Once i have been driving around for a bit it becomes very hard to shift. There is no problem at all when the tranny is cold. The clutch was recently replaced and this has been a problem both before and after replacement. I am running redline mt90 in it. I would think bad synchros would have the opposite problem, being hard to shift cold. Anyone have an idea what the problem could be?

thanks!

 

What kind of clutch do you have--linkage or hydraulic?

 

The clutch is linkage. I have tried adjusting the rod and it hasnt made much difference.

 

Shot my theory.

But try inspecting engine mounts, and all linkage and linkage pivots and mounting spots.

 

bad pilot bearing or clutch plate hub binding on trans input shaft or bad pressure plate springs or bad pressure plate fingers.