The Stovebolt Site Forums The Shop Area Engine Shop SM420 Issues

I'm not sure you are completely done with the top cover. When the 1/2 shifter shaft glides as smoothly as the 3/4 shifter shaft you will be done with that. So if more effort needs to be applied to that, try attaching the top cover to the transmission such that you can bolt one top cover bolt to the top of the transmission and the cover and shifting forks are in mid air (not in the transmission). The purpose is to use the transmission to hold the top cover so you can shift the shifter between 1st and 2nd gears and get that freed up.

The other half of the story is what you just posted. You should be able to move the clusters with your hands, they need to be able to glide over the main shaft easily. If not, it's tap, tap, tap, spray, spray, repeat until they do move. Try not to hammer the edges of the grears and wear some eye protection. I used a piece of wood and hammered on it.

This should fill in your weekend. Good luck.

If the transmission is in neutral, and you can spin the output shaft, you might try that, and then try moving back into first gear. Sometimes these transmissions won't go into gear if eveything inside isn't lined up just right. A little movement of the output shaft could make all the difference in the world.

Just got back in from the garage, and the transmission shifts into all gears great! sfsutton, you were right. The rear cluster didn't want to move on the shaft, light persuasion with a rubber mallet and pb blaster and it moves free.

Now for the test drive .

Good luck! The SM-420 in my 50 3600 was "stuck" in neutral when I got it. It took a lot of WD40 and persistence to get the shift rods to move freely. Now it works great.