Munci 4 spd and Driveshaft questions

[Jim K.]

I need to drop the tail section of the Munci unit i have in my 61 (I know, I know, but it's what I have...), I have taken the linkage and cross member support off and removed the 6 bolts holding the tail to the main case; I have the tail about 1" off but it seems that it's hung up. Does the reverse arm need to be moved around or removed? Should I have just takes the whole trans off of the bell housing? Or the entire bellhousing off of the block? The reson for the surgery to begin with is the vibration and play between the yoke and tail bushing. On the drive shaft, I may have too short of a driveshaft which may be causing the yoke not to be far enough into the tail peice. How far out from fully seated against the tail peice should the yoke come out (assuming the axle is supported on jack stands)?
Thanks!!!
Jim

[Dennis A.]

Re: Munci 4 spd and Driveshaft questions

Jim....

A few things to check out;
First: A muncie transmaission in a "61 requires a longer slip yoke - 26 spline, 4 1/2 inch X 2 1/2 inch dia. If the yoke is less than 4 1/2 inches, in time vibration will cause damage. (These extra shaft length yokes may be hard to find, check with Paragon)
Second: The bell housing must match the Muncie main housing. Special short years, like '64 muncie's vs a '63 have a larger front bearing. If I remember right, the main collar dia. is very important to get right.
Third: Install with a '62 4-speed transmission mount adapter plate and shims. this well align the original drive shaft and should be for smooth going.

[Christopher R.]

Re: Munci 4 spd and Driveshaft questions

I had the same problem last year, and ended up swapping the Muncie for a rebuilt T10. (And the shifter, and the driveshaft, and the clutch, and the flywheel, and the bell housing, and the clutch linkage, and the needle bearing pilot bushing, and more stuff I forget right now.)

1. I don't know how to get the tail section off the main case. Sounds like you're trying to get the tail section off so that you can replace the bushing where the yoke exits. Also don't know if you can do this while the transmission's in the car. Or you have to drop it.

2. That bushing would be enlarged and need replacing if you've been driving around with a short yoke. You need the longer Corvette only version. The short version is much more common. The longer yokes are around. But they're expensive (~$175). But you have to have them. You'll get vibration and ruin the bushing in any transmission without them. Problem is that the yokes for Muncies are different that those for T10s. If you're going to switch from an incorrect Muncie to a correct T10, now's the time to do it. Especially if you can't figure out how to fix your Muncie.

3. No matter what transmission you use, make sure you use the shims or spacers that go in between the frame and the crossmember. These shims/spacers lower the back end of the transmission and help with the U-joint angles. That'll help cure vibrations.

4. While the driveshaft is out, have it balanced. The place that balances it can probably do the U-joints the right way. I've always replaced U-joints by pressing them out in a vice. After 40 years, I find out I'm wrong. This method does not support one of the tangs in the driveshaft. That can result in the tangs being squeezed together, which binds the U-joint, which leads to, you guessed it, vibration.

5. If you end up also doing a clutch, have the clutch and flywheel balanced. After you have the flywheel resurfaced. If you do a clutch, also replace the pilot bushing.

[Page C.]

Re: Munci 4 spd and Driveshaft questions

Hi Jim.
There is a 1/8 inch tapered pin that pass thru the reverse boss on the Muncie tailshaft. You need to drive the pin up and out of the boss then pry the reverse lever out about 3/8 of an inch in order to disengage the reverse sliding gear inside the tail housing.
Have fun,
Page Campbell

[William C.]

Re: Munci 4 spd and Driveshaft questions

Page is correct about the pin, but I think you will find it much easier from where you are to pull the trans now and deal with it an a bench.

[Brian Monticello]

Re: Munci 4 spd and Driveshaft questions

Agree - pull the trans. Having revently rebuilt a Muncie from scratch I shudder at the thought of removing and replacing the tailshaft in the car.
Brian

[John G.]

Re: Munci 4 spd and Driveshaft questions

Yep, pull the trans .. Even if you were able to remove the tailshaft by itself with the rest of the trans still in the car it would be very tricky to try and mate the grooved reverse slider block to it's flanged counterpart on the rear of the reverse gear that rides on the mainshaft. You need to be able to at least see that these two components are fairly well aligned to one another in such a way so that they mate together properly. The tailshaft itself is slightly canted when doing this so you can see what's going on and also to make slight positioning adjustments to get the slider block and flange just so. This might take a few tries to get it right. Trying to do this operation with the trans installed in the car is doubtful, IMO. I'd be amazed to hear if others have done it this way . .! . .

In my case with my own Muncie rebuild the reverse shifter shaft stayed in place in the tailshaft housing. I couldn't get the tapered reverse lock pin removed without mushrooming the bottom of that pin, so, it stayed in place. As has already been noted the tapered pin is removed from the bottom, UP .. ! .. I was able to get around not having to remove the lock pin and thus the reverse shift rod assembly when it came time to make the slider block/reverse gear flange connection. But, the tailshaft had to be really canted to one side in order to do it. It took a couple of tries before finally making the connection ..

John

[Jim K.]

Re: Munci 4 spd and Driveshaft questions

Thanks for all of the replies, I had a feeling I was going about it wrong. I understand everything except the shims. I do get that the shimms go on top of the trans support cross member, but what type and how do I figure out how many I need? When I bought the car 4 years ago, the only drive train it had was the rear end and a driveshast (with a bad yoke), to get it going I found a vintage 327 w/ a munci and except for the vibration, it has been working. Needless to say, I had no trans mount, no munci plate and no shims. Thanks for the input, I knew I could count on you all (or is it "y'all"???)!!!
Jim

[John H.]

Re: Munci 4 spd and Driveshaft questions

1/4" to 3/8" of shims has worked for me in the past on several 57's.

[Roy B.]

Re: Munci 4 spd Longer yoke C1's

The longer trans yoke was not just for vibration ,but for safety reason.Because of the drive shaft angle to the rear end . That is the only reason for the rear banjo straps to keep the rear end drop from traveling to fare and if they broke the longer yoke was to keep the drive shaft from coming out the back end of the trans.

[Jim K.]

Thanks Everybody!!! NM *NM*

[Jim K.]

Re: Thanks Everybody!!! NM

I need more help. My original posting was after I tried to seperate the tail section. I tried to get it back together before removing the whole unit and had no luck. I now have the munci out and tried to make it close. In short, I have the thing all apart and a few small peices bouncing around, namely:
1) 17 loose roller bearings with a cage toward the front I think I can reassemble with grease to hold them together and
2) 3 - 1" long keys for lack of a better term that I have no idea where they go.
3) there is a washer/shim that sits under the reverse gear in the main case that I bent trying to close the case before I removed the whole unit, how chitcal is that being perfectly flat?
4) with the tail section off the main case, I sliped it over the yoke and there is more play in there than seems possible, like in the 1/16 to 1/8" range not 1000th's, what should I expect?
If someone could forward me a munci exploded view or point me in the direction of a manual, I will still try to put it together myself, but may bring it to a trans shop nearby who I have some faith in....
Thanks!!!
Jim