New synchro, still have problems

[SeriesShorty]

Wow, it's been forever since I've been on here.

History - Few months ago, I couldn't get into 3rd/4th after finally getting it running again. Took the gearbox out and found that the synchro was chewed up, appeared burned, and warped. Looks like it sat and spun when I (improperly) towed it last year.

New synchro in the mail yesterday. Yay! Slapped it in and it slides forward just lovely. No other problems to note. Until I put the bellhousing on. As soon as the bellhousing is fully seated the synchro doesn't move again.

Any ideas?

Thanks,
J

[scatterling]

can you get it into any gear?

[SeriesShorty]

It's still on the bench, but I can move the reverse gears and 1st/2nd by hand. I should have clarified, when the bellhousing is seated onto the main case, is when the 3rd/4th synchro stops being able to slide forward.

[I Leak Oil]

Try locking up the parking brake and rotate the input shaft while engaging the synchro. This should help line up the splines with the main shaft.

[SeriesShorty]

Locked the parking brake but no difference except that nothing spins now.

Took the bellhousing off, reset and tried it again...same thing. Grrrrr

[I Leak Oil]

Maybe a silly question but is the synchro in backwards?

[SeriesShorty]

Just got back in from checking, and it looks like (by pure luck I might add) that I installed the synchro right. Thanks for pointing that out because I totally skipped that page in the Green Bible. The end of the synchro with the recess inn splines is facing towards the rear of the gearbox so all is good there. Distance piece and constant gear appear to be in proper placement when the bellhousing is offered up.

What the heck.

[I Leak Oil]

Sounds kinda odd for sure. Only other thing I can think of without seeing it is to install the shift forks, cover and shifter and try it. If there's wear on the shaft and you don't slide the synchro evenly then it can bind a little. Never seen it so bad it won't go though.

[SeriesShorty]

I've got it! Not ever seeing one of these things before, I thought that the whole synchro was supposed to move. At least I am learning from all of my mistakes. Once I had the synchro back out I was able to push the center section forward and back and that helped me to understand how it all worked.

I reinstalled everything last night, put the top cover back on, installed the fork and gearshift. After a bit of jimmying It slipped right into 4th. A little more jimmying and it moved into 3rd. Didn't feel like it was going forward far enough though to fully engage 3rd. A little more playing and it loosened up enough that I got some more forward movement.

I took some video so I'll try to post that tonight to get everyone's opinion of if it's actually moving back and forth enough.

I needed a little renewed faith and I got it.

[scatterling]

[SeriesShorty]

Check out the video of the shifter movement. After a few tries it loosened up a bit. What ya'll think? Am I safe to button up and reinstall the lump?

http://www.youtube.com/watch?v=YoKpKorhvig

[scatterling]

you should be ok. My synchro was tight when I put it in but shifted easily when I got the truck running. Congrats. Do youself a favour though and don't put the truck completely back together again before running it. Also remember to put plenty of moly grease on the primary pinion splines, clutch splines and the bush in the flywheel when putting the gearbox back in.