Ok, A guy came in the other day with a 1962 Impala that he just bought and was having some problems with. It is a 327/ 4 speed car. It was making some strange noises in 2nd and 4th gears. So he asked me to drive it down the road and back... Take off, feels like the clutch slips a little, go to shift to 2nd... wont go... thinking it might be the shifter, i jam it down to second.... Horrible horrible noises, no power to the wheels... Get it back and put it on my lift, looking at all the shift linkage, take off the cover plate... and its just carnage... but it is a m-22 with the thick gears at 22.5 degrees... Rebuild parts are on the way... Ill get some pics... I didnt know it was possible to destroy one? Anyone else? The 327 is pretty much stock with a cam (he thinks).
Anything is breakable . . . . even the much vaunted M-22 can be destroyed if a Ronnie Sox wanna-be attempts a super fast shift and lets out the clutch too fast before the car is in the next gear. Terrible way to destroy a neat, rare transmission.
Had a early one with the thinner syncro's and broke the syncro's a couple different times. Beat the **** out of it and that was about it. That was behind a pretty stout 427 BBC..
Probably been broke before and will likely break again. Some racer probably broke it at the drag strip in a different car previously and they fixed it and put it in that car. Once they break, the cases weaken and it will break again much easier thereafter has been my experience. Think about the stress on the case when those broken teeth get between each other and the car is moving and/or the engine is at full valve float. Even for a few seconds. Unless you replace the main case, it will be a temporary fix in my opinion. Good luck.
The main case on the Muncie 4 speeds can stretch and when they do the gears that mesh get farther apart. This causes more slack between the teeth and it goes downhill from there. Also the early units had smaller diameter cluster gear shafts. Google Muncie and there are several sites that pop up for aftermarket steel cases and truly bulletproof parts to build a stronger gearbox. I raced a D gas '57 Chevy in the '60s and probably put a thousand p***es on two different M20s. I only DNF'd because of trans problems twice that I recall.
Ran an A stock Chevelle 327/ 350 hp in 65 & 66 with an M-22, never tore up gears but syncro's all the time but I only used the clutch to get it off the line, every shift after that was slam it and hope. Sometimes it works , sometimes it don't.
I agree with everyone else, the main case is wore out of tolerance allowing slop in the gears. Solution is a new main case and while your at it I would also recommend an iron midplate to eliminate flex between the main and counter shafts. They aren't even all that horrible expensive. try http://www.riversidegear.com/ They seem to have decent prices for autogear stuff. Scot
Just looked, new super main case is under 300 and iron midplate is under 200. Not all that bad in my opinion.
when I was breaking muncies in the 70's and 80's these were the go to guys they have a few tricks up their sleeve http://www.libertysgears.com/ and there still around today
Yup, I had a 64 Pontiac Tempest 326/4 spd. Took out cluster gear and second gear once, that was my first ever standard trans rebuild. Took it all apart on the bench, ordered the broken parts, opened the manual and had at it. Took a while to figure out how to get all those needle bearings inside the cluster to stay there inside the trans while I slid the shaft thru the case opening into it. I suppose a hard lesson is the most memorable....
The shift forks were and are bent. When you jamed it into gear you locked up the trans and sheared the gear set. Just what it sounds like. Never ever jam a gear if its not going in with normal shifting.
One of the great pieces of advice right there. If it doesn't go easy don't force it because then you break it.
Cases are pretty easy to fix , setup in bridgeport, index off the rear countershaft hole, bore the frt. hole oversize, make a bushing to accept the shaft, press bushing in case, press shaft into bushing. Have 1 case that's been in service for 12 years like this , another was in a car I sold years ago that I know had 80K miles on it behind a BBC. dave
Heard Sox and Martin (secretly) used a Ford toploader behind the big Hemi! supposedly held up better than Mopar trans. Ago
Thanks guys, Never thought about the case... Guy got a steal in the car, I think im going to put an m-21 in it thats good, Parts for the 22 are ridicolous. I did some figuring today... Ill talk to him tomorrow... And again, Thanks everyone, you guys are very helpful... I would have rebuilt the trans and been doing it again for free...
Glad someone has a clue around here. That's what I want to do, **** can a case because it's got some imagined stretch. If the gears are losing proper index I submit the counter bore will be showing severe wear and out of round. Seen cases crack from counter shaft bore to input bearing hole. Another news flash, ALL parts are over seas produced, it ain't 1970 anymore. I want to hear more of that bull **** about shifting with out the clutch, know I'm a**** knuckle draggers then, WTF.
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