Issue with Rebuilt M21 Muncie 4 Speed
08-31-2010, 12:35 PM
#1
Pro
Thread Starter
Issue with Rebuilt M21 Muncie 4 Speed
I'm installing a Muncie M21 that a customer had rebuilt locally (supposedly with all new gears), and the shift arms don't seem to be right. Normally, you can easily move the shift arms by hand for 1-2 and 3-4, with a neutral in between...basically, it clicks into 3 positions. This transmission only has 2 firm positions, and is very tough to get into the neutral one. basically, you have to wiggle the arm while someone else turns the rear wheel to get it to go into neutral...and then is pops back out jsut as easily. Needless to say, its impossible to adjust the Hurst shifter with it like that. The trans does have lube in it, and is installed in the car.
The builder (a guy who does them part time in his garage) claims that its just tight because of the new parts, but I have installed lots of rebuilt and new transmissions with no issues like this before. Thoughts?
The builder (a guy who does them part time in his garage) claims that its just tight because of the new parts, but I have installed lots of rebuilt and new transmissions with no issues like this before. Thoughts?
08-31-2010, 12:46 PM
#2
Safety Car
tight is one thing, impossible to move properly is another. sounds like he misaligned (or mis installed) the internal parts when he put it back together. even tight it should be able to shift into all positions.
08-31-2010, 02:51 PM
#3
Safety Car
It's not new parts (unless he's suggesting there are press-fit parts in the trans shifting/syncronizing assemblies). I'd be looking at the shift cams, bent forks, or a syncro key fit.
It sounds more like the builder's problem to sort out.
It sounds more like the builder's problem to sort out.
08-31-2010, 06:59 PM
#4
Burning Brakes
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After I rebuilt my M-21 last winter, while the tranny was out of the car I could move the shift forks through all the gears. I did seem quite a bit harder to move through the gears but I just figured it was the new syncro's. It would not pop out of gear though like you are describing. You could take off the side cover and take a peek inside it might give you indication of what might be going on. Their pretty easy to work on but they go together like a puzzle and only can go one way. I have it in the car and running now and it seems to be working just fine.
