The Stovebolt Site Forums The Shop Area Engine Shop Tranny going back together.

I ripped into my SM420 about a week ago and started putting it back together last night. I took everything out of the case, drained the mud and muck out of it, hot tanked it at work, sandblasted the outside surfaces and rinsed all of the insides really good with Brake Kleen after sandblasting. I also ran solvent over all the gears, shafts, shift forks, etc. I'm replacing all of the bearings, except for the little roller bearing on the output shaft, as well as all of the gaskets. I have a few questions, though. In reassembling the unit, do the new bearings need to be dipped in gear oil or anything or will they get adequate lubrication once it starts being used. Obviously, the lower bearings will be immersed in gear oil but the uppers won't. Also, there's some surface rust on some of the gear teeth, as well as some "sticky buildup" of some kind. It looks like the gear oil just got hot and sticky and it's hard to get it all off. Will the rust and buildup cause any problems? Is there anything I need to be aware of in putting this thing back together? It's really a simple setup and it only goes back together one way. Thanks.

That rust will rapidly wear the gear teeth and needs to come off before assembly. Try some Naval Jelly or any rust remover with Phosphoric acid in it. Don't worry about the stain left by the rust, just the abrasive surface stuff.

Use a piece of garden hose cut to just the right length to fit inside the cluster gear (including the thrust washers on the end), and pack the needle bearings around it with stiff grease. Then use the cluster gear pivot shaft to push the hose out the backside of the case as you slide it into place. It will prevent dropping a bunch of needle bearings out as you try to install the shaft. A piece of broomstick works, also!
Jerry

If the surface rust is just light it won't be a problem run a wire brush over them prior to installationin in the case. Dip your bearings. I always put the transmission in gear and roll it by hand and pour a little oil over all the bearings and gears prior to installation of the shift plate. Hope this answers your questions and good luck. Let us know how it comes out.

I coat every wear surface with a little gear lube. After installation & trans. full of lube, start it up & let the clutch out in neutral. This will spin lube everywhere in the trans.

Since you have the trany all apart you should also replace the synchro rings as well.

I would if it had 'em. All it's got in it are some gears and bearings. Thanks for all the help and info, guys. I've got to start taking some pictures and posting my progress here.

The synchros are available if you need them. Here is one place I have seen them:

http://www.hermtheoverdriveguy.com/id3.htm

Good luck.

Neil,
Did you get your tranny back together and on the road? Is it quiter? I'm thinking about yanking mine apart. It runs good but it leaks.

John,
It's not back together yet. But when it is, it'll be one clean unit! I just got my gasket kit from Jim Carter today, so I just painted the case and will put it back together tomorrow. I'm actually doing a frame-up on my '40 right now so this is just one piece of the puzzle.

I just looked at your website. Your truck is incredible! You really did an awesome job on it. I'm sure you're proud of it. I may have some restoration questions for you. I'll keep you posted on my progress.