Can ANYONE troubleshoot transmissions!

[Dirtcrasher]

Well lucky me on occasion the 87 250SX goes from 5th gear to 4th!! or from 4th to nuetral until you shift up again. 5th and 4th are not pop wheelie SX gears or gears you really jam so I'm hesitant to say bad fork. Only happened a couple of times but I don't want to make it worse. Now if the cam stopper itself or stud were bad I believe that would affect all the gears not just 4th and 5th. If the drm advances and the gear dogs engage as I'm cruising along how can it possibly rotate the other way back to fourth?? Does that mean that 5th is only patially engaging and drops out due to a gear dog problem etc??? I would guess that the gear is binding on the shaft or the 3 holes in the gear that mate the raised nubs on the other gear are damaged. Yes, I know I have to take it apart but I did take the 85 with no 1st gear apart anfd that had all it's teeth so I'm a bit confused. Where is the TRANNYMAN!!!!!!

I have complete confidence in splitting this but I could really use some of your experience in the tranny areas of improper shifting.

[MR ATC]

you answered your own question. we could make educated guess's all day but the bottom line is it still needs to come apart. time to dig in

[Dirtcrasher]

I'm glad you replied MR ATC. But the last 250SX tranny I split had some cam drum wear, the pin in the fork that rides in the cam slot and on a couple of gears in there dog engagement area or the lugs themselves. But what is considered normal?? If the corners in the gear slots or raised lugs are merely rounded must I replace them?? Obviously the drum and forks are junk but I don't want to throw away good useable gears.

Does a dry run react the same as under power, how can I be assured it will shift right without actually riding it??