The Stovebolt Site Forums The Shop Area Engine Shop SM 420 rebuild?

I purchased a SM 420 transmission from a local with the intention of putting it into my '49 half ton. It had that preservative tape wrapped around the spline shaft and looked as if it had been stored inside for many years. However, when I pulled the drain plug, the first thing that came out was about a pint of water. I removed the inspection plate and I can see some surface rust on the lower part of some of the gears, but no broken teeth, no metal shavings and everything turns as it should. My biggest concern is potential water damage to the bearings, but the water was at the very bottom of the case.
Should I roll the dice and install it as is or should I bite the bullet and have it rebuilt?

Those arn't very hard hard to work on. If you think you can do it yourself & have a little time & interest I would pull the basic componants out & check them over. Otherwise I would run it like it is. Usually a little light surface rust will lap itself in as soon as it,s run a bit.

I had exactly the same experience with my SM 420. After the pint of water came out, a heavy dark sludge followed. I figured that the tranny fluid broke down after years of sitting. I am getting mine checked over by an oldtimer who used to rebuild them. I did have a little chunk of loose metal in the bottom of the case.