Technical Muncie input shaft no good?

Now we are getting some good info here! I need that wrench!

I can see how there would be some play and to put screwdrivers behind the snap ring. Makes sense to me. Just gotta get that thin nut off. It's left hand thread right?

Thanks guys for this info. And about putting it in 2 gears to lock it. Yes I pulled the cover off to look inside. It does

 

The nut is L/H thread [don't forget this]
make your own wrench to do the job ,here's one I found on Google images.

on my one, I rounded it all to be tidy looking [ so it is a keeper.]

 

Hi When I changed the input on my m20 I did not have to disassemble the transmission. The input has a flat on the syc. ring teeth that lets you pull it out the front after the cover is removed .Watch for all the needle brg. in the end of the input shaft that supports the main shaft. It is easy to do. With the input out then change the bearing. Or buy new with new bearing.
Regards
Dave Take the side cover off also.

 

no you do not

 

I know the t5 can be done without disassembly,I've got no idea on a Muncie. I figured same concept. It looks like the teeth on the back of the input would hit the case though? I looked in back there and sorta looked like it (I'm not saying your wrong,cause I hope you are right)

 

Hi
back in 1968 I twisted my input shaft 1/2 turn in my 68 Camaro and that is all I did to put a new on in. The flat spot is so it will go past the counter shaft gear. Watch the needle bearings don't fall out.

 

I see no flat spot in the muncie shaft. I'll look again

 

Don't bother.
The flat spot they are referring to is a concave cut into the dog ring on T5's [this allows the dog ring to slide out past the countershaft drive gear.]
Muncie's don't have this concave

Muncie input.[rear]


T5 input [rear]

 

You want to take it all apart, so you can find all the other problems. Welcome to old transmission repair.

Sent from my Trimline

 

That's why I'm wondering how they say they have done it before. I don't see it being possible.
You are correct about the inputs being different

 

I'm not taking this thing all the way apart. I don't see a need to. It looks good inside,synchros look good. Front bearing needs replacing due to the cage starting to come apart,which I think can be done without removing the input as mentioned above.

Going to plug the 4th gear sensor thing in the side cover also.

Forks look worn but I cleaned them up a little and I don't see why they wouldn't work. Maybe a little more movement than new but don't think it's going to be that bad

 

Must be a later Muncie (post 68), it should also have the 3/8" bolts attaching the shift levers. The one I put in my 67 Nova was like that, I wanted to use the earlier style shifter that uses the 5/16" threaded stud/nut arrangement so swapped to a complete 66 side cover assembly.

 

The way I see it is: You can take it apart and check everything now. Or, you can put it in, run it and fix it if it breaks. The only problem is, if it breaks you have to take it back out, take it apart and replace everything that was originally bad plus whatever else gets effed up when it breaks. And then, put it back in again.

A couple of hours now, or many more later.

 

As I said I have checked all the teeth, synchros look good,so why would it break????

 

I think you can get the input out by prying against the bearing snap ring and tapping to input back until you get the bearing off .Then you can jack up the mainshaft and get the synchro teeth to clear the case. It's kind of a light press fit , I seem to remember. It's still a PITA to do it that way too.
You're supposed to use a shortened dummy cluster shaft, and drop it down out of the way..

 

There is a lot the naked eye can't see just looking in the side cover opening.
My M-20 was built by a trans shop owner from his stockpile of hard parts and rebuild components, there was a hairline crack in a synchro cone that he missed, fixed it but took two R&R"s. If youre feeling lucky añd don't mind wasting a day or two of your time just stab it in and take your chances.

Here is a very good article, read the tips for free you don't have to buy the book but if you plan on rebuilding a Muncie in the future I highly recommend getting some knowledge.
https://www.chevydiy.com/how-to-inspect-and-repair-muncie-4-speed-transmissions/

 

maybe a piece of broomstick cut to length to make a dummy shaft. I think the manual suggests removing the bearing from the main drive gear (aka input shaft). but I'm too lazy to read up on it. here you go

http://selectric.org/manuals/muncie/index.html

 

Well,yeah you are right. Of course there's always a what if. Supposedly this was taken out to put in a 700r I think cause he was older and wanted an auto.

 

I've heard a broomstick mentioned before. Forgive my ignorance,how would this be used?

 

you just need a shaft that is the right diameter to fit into the roller bearings in the cluster gear, and only as long as the cluster gear (shorter than the countershaft, on which the cluster gear rides). You push the dummy shaft into the transmission to push the countershaft out, then the cluster gear can drop down, and the dummy shaft holds the bearing rollers from falling out of position.

 

Just got off the phone with 5speeds .com,he's famous for being a Muncie guru. He says it's not possible to remove the input shaft without total disassembly.

So I'll just try to remove the bearing round the shaft and make an extended pilot bushing.

 

I take it this is after you remove the tail,and the midplate that holds the mainshaft is pulledout? Basically taking the trans apart?

 

yup.

Usually I just let all the rollers fall out as I disassemble the transmission, and put them back in with grease and patience. After cleaning and inspecting everything. You never know what surprises you'll find deep inside a 50 year old Muncie 4 speed. They usually led a hard life.

 

Yup again. Just get a small parts kit (after inspecting the big parts) and don't fight it.

 

I'm going to get the bearing,and gasket set,if I can get the bearing out and put it back I'll run it with a longer pilot bearing.

If the needle bearings fall out,I'll just order the input and let it sit and take it apart to change it.

 

You guys probably are not following this, but I changed the front bearing. It wasn't hard. And the input I don't think would come out the front. So all those saying they have done it,is like to know how because there is no flat spot on a Muncie input.

I'm down to looking for a extended pilot bearing. Think I need to find someone to make one. Although my pilot shaft measures 6 1/4 to mounting face and someone mentioned above that his was 6 1/2. The extended pilots are 1/4 so that would in theory be the ticket

 

What would you make the extended bushing out of? They are made to be fully-supported and not hanging out since the right material is a bronze alloy.

 

you could turn down the OD of a stock bushing, and turn a steel tube to fit into the crank, and fit the bushing into the tube. That might require access to a lathe.

 

Extended pilot bearings are made with a shoulder,a normal bearing is just straight,the extended ones go into the crank up to the shoulder that is bigger than the rest of the bushing so it gives it some strength.

Though I have seen a lot of ppl leave a standard bearing out by 1/8. I'd assume it could be done with an extended bearing as well. I'll have to get the trans back in there and ty to see how much on the shaft is going into the crank

 

You got it, a shoulder is a must to give it strength. I can come up with 2 or 3 ways to make it work.