Been driving my '56 for about a year now and the M22 that is in it finally gave up 3rd and 4th gears. I'm sure it's a synchro issue, but afraid it may be the shift collars and not just the synchro rings. Regardless, I have an M21 that was rebuilt about 10 years ago and has been sitting in the garage ever since....it has never been used. I need to yank the M22 and have it rebuilt, but I also need to drive the truck, so I was going to put the M21 and run it, maybe indefinitely and just save the M22. PROBLEM: The M21, which was free spinning before this last winter, is now bound up. The damn thing will NOT rotate. I took the side plate off and there was some minor surface rust, so I soaked it in ATF and that seems to have removed 90% of it. But, it's still bound up. It has a yoke on the output side, and at first I thought it was one that was bolted on the end of the output shaft (hadn't looked at it for years) but it's not. The REASON I thought so is that it absolutely will not slip off. Am I missing something? Aren't all of these yokes slip yokes? Could it have been dropped on that end and jammed the slip yoke in there...maybe that would explain why it's froze up? Everything inside looks good...I can't figure this out. I've run a kingpin through the two yoke starps and tried to pound it off with a 1 lb hammer...do I need to just try a bigger hammer?
The inside splines on the yoke are tapered deep inside, if the trans was dropped on the yoke it will be very difficult to remove.(ask me how I know). Use a BFH, Do not hit the tail shaft as it can deform the seal area. BTY you will have to change your clutch disk.........
UPDATE: I ended up using a BFH and did get the slip yoke off. Ironically, the trans was still not turning. Turns out the lower countershaft pin was pushed too far into the center plate of the transmission and the countershaft gears were jammed up against the inside of the case, but even worse, the lower 2 or 3 teeth of each gear had been sitting in a rust soup and were very slightly pitted. I ended up completely dismantling the transmission and cleaning every single piece by hand, whether with emery cloth, a wire brush or a file (to get rust scale off). The transmission works fine after install, but whines in 2nd and 3rd (irregular gear surfaces I mentioned). this is a temporary transmission at best...the M22 is going to go back in after rebuild. Thanks for all the help guys.
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