lichen

Now third and fourth gear won't engage. Ideas?

oliver foster

I would start looking at rebuilt NV-4500s.
Or if you can afford to have the truck down for longer, look at getting yours rebuilt.

patdaly

Won't engage as in shifter is stuck and wont move or shifter just goes to position and nothing is engaged?

If it is trying to engage and you just can't get it in, then yea, rebuild time. If it is floppy, you might have just broken the shift fork, slim chance you can just replace the fork.

Not a lot of hope though.

lichen

Specifically, is an idea what I will find or what to look for when I take it apart. I will attempt to rebuild it myself if possible.

j_martin

Gears should be smooth, not gouged. Bearings should be round, not square.

Usually when you run em out of oil, you do a lot of damage, as when the first loaded gear starts spalling, the debris gets into everything else and starts a chain reaction.

gorms

Any bearing can be replaced, but if the race spins because the bearing got hot and locked up then you need more then a new needle bearing and race, ie machine back to specs. If you disassemble need to inspect mainshaft for galling especially. Might be able to assess some damage through the shifter on the 3-4 shift issue, ride on the same fork.