devlman

iTrader: (13)

Maybe someone with more transmission knowledge and experience can answer this for me:

I'm assembling the 93 FD trans after a rebuild and noticed a potential issue with the first-gear synchro. It's got three keyways that match up fine with the spring-loaded keys in the clutch hub, but the three fused-together teeth locations on the synchro are offset (by about 45 degrees) from the keyways. When everything's assembled, it's impossible to shift the clutch hub sleeve from neutral or second to first gear because the large spaces in the sleeve need to line up with BOTH the keyway on the clutch hub AND the fused teeth on the synchro in order to get into first gear. But since these two are offset, they never can line up without something else going on. The only way I can make it happen is by pulling the sleeve into second gear and manually moving the spring-loaded keys and 1st synchro apart so the synchro can spin freely and line its fused teeth up with the space in the clutch hub. But once the synchro spins about a quarter turn it snaps the keys back into place in the keyway and the synchro is once again unable to turn.

The shop manual mentions the three fused points and how you need to to line up the synchro's slots with the keyways as I've done--everything looks totally fine. What's bugging the hell out of me is how the transmission ever gets into first gear! I know I pulled it into first manually when I took it apart to lock the mainshaft for locknut removal and it dropped in without much fuss then, but now something just doesn't seem right. The only thing I can figure (short of something being installed wrong) is that somehow the keys are forced out of the keyway temrporaily to let the synchro spin and line itself up when shifting into first. But I don't want to find out something's wrong AFTER I get the trans totally reassembled. Anyone know what I'm talking about or have any insight? Did I just miss something obvious?

Thanks

Jon

devlman

iTrader: (13)

Any thoughts? Trying to get the tranny back together today....

GARCO MOTORWORKS

If you line the synchring grooves with the keys and the clearance is in spec then the hub should shift .I have never had one that did not work correctly .Assemble the trans and shift through all the gears before installing it .pre lub everything as you assemble .

Trexthe3rd

It is done this way to prevent shifting into 1st gear from high rpm to prevent damage.