Help! Stuck in Gear

[Kicnrocks]

I have a 1968 427/435 4 speed that has become stuck in first gear, stick is mobile, I read that on some of the transmissions a pin falls out that prevents the gears from being shifted. I have had a look and nothing from the linkage appears to be the issue. MY question is do I have to remove the linkage and cover housing to locate the "pin" ?., and if so can it be easily observed once open? Or is their another way to solve this problem?
Clutch is working well.

 

[GTR1999]

The pin is in the side cover, if it slipped in you will see it from outside. I think the 68's used the better pin but I'm only going by memory here. To engage a gear the linkage has to move the fork,then the slider on the main shaft. If the pin looks ok and you can get at the trans,then remove the linkage from the trans and see if you can get a adjustable wrench on the lever in the cover to move it into neutral and then gear. There are 2 levers in the cover, the rear one is for 1-2 and the forward one is 3-4.

Here is a Muncie

Here is a 69 cover with the good pin

Inside the cover

 

[Kicnrocks]

Thank you Gary, Great answer and great photos, Kevin

 

[Hib Halverson]

To my knowledge there is no "pin" that can fall out and render the transmission "unshiftable".

There are retaining clips that hold the ends of the shift rods to the shift levers on the side cover and the shift arms of the shifter. If one of those clips comes off, either the rod disconnects or it comes partially out of the hole on the shift lever or shift arm. Either way, the trans either gets stuck in gear or neutral or gets jammed between gears.

If the trans is stuck in first gear, get under the car, put a 9/16 wrench on the bolt or nut holding the 1-2 shift lever and see if you can move the lever back to neutral. Then inspect the linkage for faulty retaining clips, worn parts or incorrect adjustment.

If the problem cannot be fixed with a linkage repair or adjustment, then you may need to remove the transmission for repair.

 

[GTR1999]

Hib,
The early Muncies had a straight pin on the cover holding the shift combs. It was replaced with a flanged pin show in my pictures, sometimes they did loosen up.

 

[Hib Halverson]

This week, I'm blind. I don't see the pins but....do those pins just loosen up, or do they fall out?

Also, what's a "shift comb"?

I've had a Muncie or two apart but not often enough to be familiar with that term.

 

[GTR1999]

Look at my picutes of inside the cover. The "combs" are the levers that move the forks,the forks pivot on the pin. The 2nd design pins have a flanged head so they can't move into the transmission.

 

[Hib Halverson]

"Combs". Oh....I get it now. Those are the things most people call "shift forks". Must be a Northeast "thing".
:L

What I don't understand...again, I've only had a couple of Muncies apart in my life...how could the shift fork move towards the inside far enough to "fall out"?

I know I'm showing my ignorance but....

If the pin does come out, does that render the trans "unshiftable"?

 

[GTR1999]

Hib
The fork won't fall out since it's riding in the slider groove, the pin holds the combs/spring which is what locks the fork in place. The forks slide into the arms which are the tapped end out of the cover.

Here is a Muncie main shaft, you can see the sliders and where the forks will fit into them. Shifting would be a problem as would be getting into neutral.

 

[JohnZ]

"Combs". Oh....I get it now. Those are the things most people call "shift forks". Must be a Northeast "thing".
:L

What I don't understand...again, I've only had a couple of Muncies apart in my life...how could the shift fork move towards the inside far enough to "fall out"?

I know I'm showing my ignorance but....

If the pin does come out, does that render the trans "unshiftable"?

Hib -

Look at the bottom photo in Gary's post #2. Note the pivot pin in the center of the photo with the "E-clip" retainer on it, which holds the two spring-loaded stamped sheet metal pieces in place. Each of those two pieces has a "rooster comb" shape on their bottom edge, which rides on a machined surface on the shift fork - they keep each fork from shifting unless the other fork is in the neutral position. If that pivot pin comes loose and falls into the transmission, it becomes "unshiftable". The first photo in that post shows the flanged end of the pin on the outside of the cover; early Muncie pins weren't flanged.