5th gear problem

[h22hatch91]

i just did a b16 motor swap and when i drive around or whatever it will automaticly slip out of 5th gear and go into neutral. it seems it only slips when the car has been running for a while because if i go into my car right now and go out and drive it would be fine until a little while after the motor has warmed up then it will continue to slip. any idea on what is causing it to slip out of 5th ? .............thanks

[Jos4DCivic]

sounds like it could be bad syncro. does it grind at all going into 5th?
if the car jumps out gear into neutral,particularly when decelerating or going down hills,first check the shift lever and internal gearshift linkage. excessive clearance between gears and the input shaft or badly worn bearings can cause jumping out of gear. other internal tranny parts to inspect are the clutch pilot bearing,gear teeth,shift forks,shift rails,and springs.

Good luck