The Stovebolt Site Forums The Shop Area Engine Shop 2 questions

I've been working on my barn find '54 3600, which sat inside since 1975. Today I drained the oil in the engine and tranny and got 2 surprises... a little anti-freeze in the crankcase and it appears chunks of a roller bearing ? came out with the 3spd's tranny oil!
My questions; 1 What should I do before I try to start this engine - tighten the head bolts? and cross my fingers? I'm nervous the block may have gotten a crack one winter while sitting here in Maine. 2 Is a 4spd tranny the same length as a 3spd - so it would just drop in with no modification to the drive shaft.
Any help would be appreciated

whatever you do, don't run it! If theres anti-freeze in the oil, then the head could be cracked. If you know how to re-build an engine, tear it down and look for cracks in the head, or take it to a shop and have them inspect it. someone else could instruct you better, but dont run the engine, thats all I can say. And, it sound like your tranny has a few problems too. Have that checked out, or tear it down yourself.

Hopefully, there wasn't much coolant in your crankcase. The two biggest culprits are the headgasket and a cracked head or block. The right stopleak might fix either one. Yes, antifreeze can ruin your bearings, but a small amount won't hurt much, and if you are going to have to build a new engine sooner or later, it won't make that much difference. We had a fire truck with a major crack in the block, they put 4 cans of alumi-seal in it, and ran it for 3 or 4 years before the truck was sold, and it still ran.

As for your tranny, are you saying you have a 3 speed in a 3/4 ton? I thought they all had the SM420, 4 speed granny box. While I don't think they are the same length, your driveshaft should have a slip joint in it that will allow for some adjustment. Is your shaft open the full length, or is the front half closed?

Fred,
It has the wimpy (not heavy Duty 3 spd) and all appears original, including the completely open driveline. I was planning on a 4 spd conversion eventually anyway, so now wouldn't be a horrible time. I have looked around on line a little and noticed the earlier 4 spds look to be set up for torque tube - is this easy to change over or should I look for a later model (post 55)?
The oil only appears to have a small amount (1/4 cup ?) of antifreeze in it, and I plan on doing a compression test and possibly a pressure test on the radiator before starting it. Hopefully it's only a blown gasket.

The heavier '54 and '55.1 models had the open driveline, and the SM420 gearbox. In those years, only the 1/2 ton trucks retained the torque tube, which of course is the reason there are no 1/2 ton NAPCOs until '55.2.

Just about any GM 4 speed granny box will bolt to your bell housing. The SM420 (reverse left and down) was built until 67, after that the SM465 (reverse right and down) was used. Best thing to do is find a junkyard and measure the length to compare. Also, you can unhook your driveshaft and see how much fore and aft movement there is in the slip joint. Just don't run it clear to one end.

On the antifreeze, I would flush all of the coolant out and run only water until either the problem is found or it gets too cold. I don't know which end of Maine you're in, but you should have a few days left before the snow flies!