nibze

I have a 1970 with a 4 speed muncie that is slowly leaking from what looks like every possible place it can leak.

My plan is to rebuild it, but I've never done that before, so I figured I would get some practice first.

I've done a bunch of research, watched everything muncie related on youtube and bought the muncie rebuild book. I bought a used muncie about a year ago, disassembled it and am in the process of doing the rebuild now. If all goes well, I'll swap in the rebuild and then do it all again for the original.

I'm going to keep a log of my progress here. If I run into issues, hopefully someone can help out or maybe what I post will be helpful for someone else.

nibze

Here is what I'll be rebuliding

Jud Chapin

I rebuilt mine many years ago with help from the co. I got some parts from. Actually was a piece of cake and I needed very little help.

I did take several what I considered questionable items to the parts supplier (local) and he helped me indicating which parts needed replacement and those that didn't that I thought did. In case you don't know, there is a special tool required for installing a particular part which I bought and later resold for basically a wash. I forget the part needing the tool but recall it involved a sleeve for the output shaft.

Today there is tons of info out there with all the internet videos you mention which weren't available when I did mine.

Anyway, I'm sure you'll have no trouble. Good luck and have fun.

RubyRedMetallic

I did my m22. It was easy. The tool is a thin wrench for the shaft nut. Rent one. You'll never use it again. Make sure that pin is tight or get a bushing done. I bought a new super case to avoid that. I wanted the thicker casting anyway.

Chris Hewitt

I really enjoyed my M21 rebuild project. Very gratifying. Used Paul C book, videos and parts. He’s the Man.

Chris Hewitt

Aftermath of my M21 locking up at 70 mph. 1st gear decided to weld itself to the main shaft while I was in 3rd gear.

drspencer

Can I assume this happened before you rebuilt your Muncie?

If so, do you now know what caused the transmission to fail?

Thanks

drspencer

'71 350/270, 4-Speed.

I subscribed to this thread because my Muncie is leaking and I'm probably going to take it out to reseal it. It's not leaking so much that the car is inoperable, it just bothers me knowing that it leaks. My long game is to replace it with a 5-Speed, so I have no plans to rebuild it, just reseal it to stop it from leaking.

Having said that, should I also plan on replacing the clutch while the 4-Speed is removed and being resealed? The trans presently shifts and functions perfectly. No complaints, at all.

Thanks

Chris Hewitt

Yes this incident is what led to the rebuild. My theory is that lack of lubrication between the shaft and 1st gear/bushing caused it. The car sat for 30 years and I believe corrosion / gunk blocked the oil channel in the bushing. The new bushing designed by Paul C has a much larger oil channel.

Chris Hewitt

Paul Cs 1st gear bushing is on the left, AutoGear is on the right. Both are way improved over origina

l design which has a very shallow channel.

Rescue Rogers

I did like you did, watched Paul Cangialosis rebuild videos bought the parts here https://www.5speeds.com/cart/index.p...&path=75_17_69 here https://www.thegearbox.org/Muncie.html or from autogear but they dont seem to sell parts anymore and used his book as well

his facebbook page is /Gearboxvideo/

best way to do it. And while the case is out drill it for a drain and add a magnet, if you have a stock one stab it with a screwdriver, i bet it pops off the case

crf311

My 4 speed will be coming out in the near future. Not sure if I'm going back in with a rebuild of putting a TKX 5 speed in.

cottoneg

You live in NYC? There are 2 guys known for their ability to rebuild the Muncie. One is Paul Cangialosi who wrote the book on it (literally): Muncie 4-Speed Transmissions: How to Rebuild and Modify (Workbench How-to) Paperback – October 21, 2014. I believe he is in Florida.

The other is Larry Fischer of D & L Transmission. He is in Huntington, NY, which isn’t too far for you. He rebuilt mine and considering how well know he is, his prices are extremely reasonable.

I personally would recommend using someone like Larry unless you are very sure you can disassemble and reassemble the Muncie correctly. I just didn’t want to get involved with all the tiny parts like needle bearing (see pic). Plus Paul and Larry have access to great parts that are Italian made, not Chinese crap. My 2cents for the day.

PHulst

Does Larry still do Muncie work?

I looked for him recently and everything I could find indicated his business was now closed.

cottoneg

Larry is still in buisness. Great guy. His business card lists his number as 631-351-4837. He rebuilt mine just 3 weeks ago.
He fixed my issue and a lot of mistakes others, less talented, had left behind in my Muncie.

tfringo

Muncie will do that if too low on fluid. That gear is floating on a collar that is pressed on. They addressed this issue in the aftermarket world by adding a groove in that collar to provide extra lubrication.

GTR1999

Roller bearing for first gear is an option as well. It's a very old mod that came about because of the gear seizing on the main shaft. I built a few Muncie's and used them, but you need a new gear with a larger bore.

nibze

wow, lots of posts on this thread since it started. lots of great information, thanks everyone

of course keeping a log of my progress hasn't really happened since been busy with work and don't have much time

but i have made progress. I have all of the sub-assemblies together - side cover, tail housing, input shaft, main shaft. I ran into a few difficulties, but was able to figure them out.

yesterday I started to put stuff back into the case, starting with the cluster gear and the input shaft. I'm having problems getting the input shaft bearing to fit in the case. I can barely get the input bearing started and when I do, its not straight/flush with the case. I tried pressing it in hoping that would get it to even out, but it didn't. I put the entire input shaft into the freezer over night and that made it easier to get started, but it still started at an angle.

I dug out the old input bearing and I was able to push that into the case (without the input shaft) about half way by hand and it seemed to go in much straighter.

Any tips for getting the input shaft into the case? The bearing is from 5speeds.com and the case is the original case with the number 3925661

Thanks!

Chris Hewitt

I would try some emory cloth on the case opening and put a little chamfer on the edge. Mine went in easy.

Chris Hewitt

For reference.