ok heres a good problem for you problem solvers. i have a 84 nwc t-5 behing my 305. and i rebuilt it and ever since i rebuilt it 5th gear keeps walking past the snap ring that holds it on. im like wtf. its the same snap ring as before. same 5th gear as before. same tail shaft as before. the splines ont he shaft arent damaged at all. ive tried putting a smaller snap ring on (and you know that didnt work out well) ive tried putting this high temp thread locker on and it worked for a little bit but the gear still pushes the snap ring off and slides down the shaft.

soooo, how do i fix my 5th gear?

 

Get a new snap ring.

Might also want to check and make sure that the mainshaft is securely pressed into its bearing, and that the clutch gear/mainshaft preload is adequate. If the shaft moves forward farther than the play of the gear on the shaft, it's pretty much guaranteed to hammer the snap ring off.

 

ive tried a new snap ring but switched back to the old one...
im pretty sure the mainshaft is pressed into the bearing all the way, mind pointing out which bearing though? its the one on the end of the case between the tail cone right, that bearing doesnt stay until the tail cone is on.
and im pretty sure the preload is good, ill check on that.