H Farmall transmission

I have a 39 H with bad tranny,will a 46 transmission interchange by swapping out complete transmissions cases?

Unless someone overrules me, I don't see why not. Just yesterday I finished disassembling the trans on a '41 H and as far as I can tell all the parts are the same as all other H's. As far as I can tell, an H is an H, regardless of year, at least as far as the drive train goes. BTW, you don't have to split the tractor to completely disassemble the trans on an H. Just follow the steps in YT's service manual and it all comes apart.

On mine, the input pilot bearing failed to the point of disintegration and my first thought was simply swap my healthy front half to a different rear half. But, you have no way of knowing how good another rear half would be, so I disassembled mine. All six bearings show enough wear to need replacing. Except for one, the gears all look OK. Plus, I need a different upper main shaft 'cause the bolt that holds the pilot bearing snapped off and I can't get the stub out of the shaft.

A fellow I know said he'd swap the entire rear half for $250, and I'll probably go through that in parts, seals, and gaskets, but I'll know what I have when it's done. Parts seem to be readily available, even from our local CaseIH dealer.

Keep us posted.

Why don't you sell the '39 to somebody who wants it for a '39? I guess you could swap the covers and it would still have the '39 cover.

I'm certainly not an expert, but I think there were some differences between the '39, early '40, and the later tractors, but those differences were mostly internal. Swapping out the complete transmission, housing and all, should be basically just a nuts and bolts operation.