The Stovebolt Site Forums The Shop Area Engine Shop Rebuilt my tranny!........but not working right

Hello everyone, I'm stumped and frustrated.

I've been trying to get my SM420 working for a couple days now, have it all together but when I try to turn the input shaft it either won't turn (if the 1st reverse gears is back)or it will rock back and forth a bit. (1st/reverse forward)

If I tap the mainshaft (propeller shaft) forward it shoves the clutch gear bearing out a bit from the case but allows the mainshaft to turn unless I slide 1st and reverse back all the way.

Could it be that I didn't get the pilot end into the roller bearings (inside clutch gear) properly?

If I'm remembering the sequence correctly, the mainshaft assembly did fall out part way after I finished tapping the clutch gear and bearing in. I lifted the mainshaft and jammed in back in. (or worse! would one of the roller bearings falling out (again) cause this problem?)

My mother would wash my mouth out if I said one tenth the words this tranny has inspired. I must be doing something wrong. Any advice would be VERY much appreciated.

Sincerely,
Jacob

If you are doing all this with the cover off maybe you are getting it in 1st & reverse at the same time. Other wise you may have dropped a roller inside the main drive gear. Pack them in a long fiber grease before assembly. Or you may have a thrust washer on the wrong side of the gear.

Thanks Wrenchbender. I'll take her back apart and double check everything.

Just thought of something. The mainshaft and everything seem to turn just fine until I tighten down the back cover plate.

Any ideas?

Thanks,
Jacob Marshall

If you put new bearings in sometimes the snap ring around the outside of the bearings are different. You may have to use the snap ring from the old bearing. I still think you dropped a roller inside the main drive gear.