Is it possible to weld the transmission case on my 49' F2? There is a crack in the lower section of the gearbox. I assume its made of cast iron.

 

Cast iron is almost impossible to weld, with any degree of strength.I've seen people braze it, and it held, but I dont have much faith in it.You have to preheat it and keep it hot for a certain amount of time and let it cool gradually.It can be done, but it is like I said almost impossible.Like my daddy always said you can cut a redwood tree down with a pocket knife, but WHY?? Sometimes it aint' worth the effort

 

It is possible, but you have to be a real pro. I had my exhaust manifold welded up at a specialty cylinder head shop. The cheaper bet might be to find a new one, but it cost me about $120 to have mine welded for what it's worth. You don't want someone to just TRY to weld it, using a torch to keep it warm, etc. You need a shop that has ovens and can keep it extremely hot so it can cool down over hours or days. These guys in Kansas City did a beautiful job, if you're anywhere close to there.

 

Try some JB Weld on it. Don't use it on the inside (It might let go and get in the gears.)
Clean the case real good with a degreaser, then wash it with dish soap and rinse well.

 

JB weld may seal up a crack but will give little if any strenght. Search 'metal stiching' or in some cases the part can be drilled and tapped and a bolt can be installed.

 

Is this why your engine wouldn't turn? Is the trans locked up?

 

I am no expert welder but I have welded cast iron with good success on a few ocassions. Might be just dumb luck but the few times I tried it the results were excellent. The process I used was to grind out the crack until you have a nice "V", drill the end of the crack if it looks like it's going to run. Then heat up the piece you are welding with an O/A torch until the area around the crack is glowing. Next arc weld the crack closed with nickel rod. Place the piece in a very hot oven (if it's clean then your wife may not have a problem with this)...over the course of a few hours gradually lower the temp on the oven until you get back down to room temp. If the piece cools too fast it will crack.
If you don't like that process or don't have the equipment, then go out on the MuggyWeld site and buy some of his cast iron repair rod. I haven't personally used the cast iron product but I have used his rod on pot metal and aluminum with good results.

 

Charlie has the correct advise, and is the same method used by a welder here at work. Prep, preheat, high nickel content rod, and cool down very slowly. If you wife frowns at using the oven, cover it in sand, this will also hold in the heat and allow it to cool slowly.

 

Ross, no this is not why the engine was tight, transmission is free but I believe the trans got water in it and it froze, hence the crack. I'll post some pics of it tonight. As for the engine being tight, still a mystery. Machinist said engine looks ok. Must have been a accumulation of friction due to dirt and gunk. Now its a ton of time to free the valves.

 

I wouldn't waste my time repairing the old tranny. The heavy four speeds are a dime a dozen. They show up on eBay on a regular basis and usually never sell or sell for dirt cheap. I just scrapped one over the weekend. If there are any junkyard in your area that have old trucks I would bet there are a couple with the trannies in them. Usually the engines are taken, leaving the tranny sitting in the truck. The way it sounds your' engine's a long way from running. Use the time it's in the shop to find a replacement transmission.

If you decide to look for another tranny make sure you get the same one. They made two types of four speeds, the non-synchro, which is the stock one in a '49 and the synchronized one that was an option and later stock. You can easily tell them apart by the shift pattern. The non-sychro had reverse over to the right and down. The synchronized has reverse over to the right and up. The synchronized tranny is about 1"-1 1/2" longer and would need the rear tranny mount on the frame to be modified to fit in your '49.

 

Bob, thats exactly what I am doing: waiting for my flathead to come alive, hence I have spare time to focus on other items.

 

DARN, Foiled again.
I wanted to see what would happen with the JB Weld.

 

Hey Dick, the back of the JB weld package has a testimony that someone repaired a cracked tractor head. Good stuff buddy!

 

I might be a little late with this answer, but you can grind it out than weld it with arctec supercast 90 rods they work great

 

Depending which way it's cracked, the gear separation forces would be continually trying to open the crack, or the thrust forces to open it. Take your pick. Not a candidate for a welded repair. Especially when hardly anyone wants that model trans anymore and there are a bunch on eBay for $25.

If this is an F-2, I would have expected it to have the rearward-mounted crossmember already. If it does, there are a bunch of trannies including the 4sp/OD from '80's trucks should fit.