The Stovebolt Site Forums The Shop Area Driveline 1967 SM420 1st gear assembly question

I am rebuilding a 67 Sm420 transmission. I downloaded the overhaul manual that "54 3600" had posted. The manual is for older SM420's & does not mention the problem I have. On the inside opening of the 1st speed sliding gear there are 2 metal snap rings that snap into 2 separate grooves. Inside the bottom of each groove is a rubber strip. I'm guessing these are for applying tension between the gear & main shaft. Also the rings are wavy not flat & have 2 teeth opposite the ring opening. This gear did move on the main shaft before it was disassembled but it was pretty tight. I'm having trouble getting the gear back on the counter shaft. My questions are, what are these for, do the rubber strips belong in the grooves , is there a certain orientation for these rings to be installed & is there a trick to getting the gear onto the main shaft? Here's a video that I hope helps make sense of all of this . Thanks Mark

I called Novak conversions & I explained my problem & that my rebuild kit did not come from them. They said no problem & helped me out. The salesman transferred me to a rebuild mechanic named Jeff , he watched the video & said he would check with another builder & call me back. He called back & said they have seen 1st gears with 1 ring but never 2. The rubber does belong in the groove & they believe the rings are for reducing chatter between the gear & main shaft. As far as orientation he said the single rings have 4 teeth & they are are set on the ring with 2 @ 12 o'clock & 2 @ 6. So that's how I installed the 2 rings in mine. As far as install I just took my time & worked the ring into the groove & slowly tapped the gear on the main shaft with a plastic hammer. Jeff spent at least 40 minutes on the phone with me & answered other questions for me as well. I have another 420 to rebuild & will definitely get all my parts from them.Novak SM420 link See ya! Mark

SWEET! Glad you got it back together, and thanks a binch for sharing your great experience from Novak's. I will be rebuilding one of these someday for my 2-ton and this has made my decision to buy the parts from them.