Why not just tear the trans down?? They come apart easy, think not much can be frozen in them if saveable. Once that front bearing retainer is off it, and front shaft pulled out, much of it should just come out easy. Watch for dropping all the little bearing rollers between top main shafts. 13 of them, find them all! Bottom shaft might need a little more soaking to get out. Real easy to break off that little bolt that holds the metal retainer on outside of case in back. Once retainer is off, the shaft should bump out of that gear cluster. That is on bronze bushings and may not be held as hard as you might think. Those bushings and most bearings can still be gotten. If the teeth on gears are gone or bad pitted, will be issue. I've used pitted ones over, but trans is noisy then, even tho it works. I have a blaster and do all the parts of the trans, cept bearings and usually come pretty clean, enough to inspect and decide on re-use. Buying gears can get expensive, times some on epay lot cheaper. Might be cheaper to buy another better shape trans if real bad shape. If you buy bearings, make sure to get one side sealed bearings, so the fluids will not be leaking out once in tractor, a common problem with non-sealed ones.