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Which Muncie???

4K views 105 replies 15 participants last post by  lwlevens 
#1 ·
Would like to install a Muncie for my 72. So if anyone can tell me which year Muncie would work/fit and what else I would need. Either m20,m21,or m22 Thanks!
 
#51 ·
That is correct. Put the trans in 1st, line up the timing mark on the balancer with the zero on the pointer. Mark the driveshaft so you can tell one complete revolution. Turn the balancer, counting turns, until the driveshaft turn once and stop. See how many turns of the balancer. 2 1/2 (2.54), a little over 2 3/4 (2.84), a little over 3 (3.11), 3 1/2 (3.50).
My 2 cents, I always liked the M20 Muncie's ratios the best.
 
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#54 ·
The M20 will feel exactly the same as the Saginaw as far as acceleration but you will gain strength. With an M21 Muncie you will have to slip the clutch more starting out and you will lose a little acceleration due to the higher gearing in 1st, 2nd & 3rd.
 
#57 · (Edited)
I was just replying to Jims63s hypothetically.(Don't know why he said that) I know I won't lose any acceleration with 4.11's it takes off now like a raped ape. The M20 I like to use is almost the same ratio as my Saginaw. So I would just gain strength from using the M20.

Sorry read Jims63s post wrong he was talking about the M21 (2.20 ratio) that I would lose acceleration with not the M20.👍
 
#58 ·
So I would just gain strength from using the M20.
Depends on who built it, how it was built and with what parts... Could be weaker, actually... But, if it's a semi-decent build, should be far stronger than the Sag box.
 
#68 ·
One thing, I would start by replacing the font bearing retainer immediately before putting a new throw-out bearing and clutch in it.

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Just make sure you get the correct one and you'll be helping your Muncie live a much longer life and they're super easy to install too. Don't have to do much of anything but clean up the surface a tiny bit.


Paul has 'em in stock in a few different configurations (only a suggestion as to where to purchase, not an ad or endorsement although he's awesome!!!).
 
#74 ·
Listen brother I don't think I can tear down the trans just to change the front bearing. I mean I probably can but don't think I can put it back together though.😳 I'm gonna change out the side cover shifter seals and rear seal for sure that I know I can handle.😁
 
#75 ·
Not the bearing, just the front bearing "retainer" it's literally 4 bolts and some French Locks... Super easy and your transmission and other related parts will thank you in the long run...
 
#80 ·
Ok took off the front snout help me out here. View attachment 445935 View attachment 445936
Ya need a new retainer for sure (at least). The one you pulled is roached!
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I would question the "rebuilt" part of the statement "it's been rebuilt" as to the origin of the rebuild and who did it?!? Can't really tell much else from this vantage point but once you drain it and collect the gear oil in a white drain pan (use an old bleach jug cut horizontally to catch the oil) and see what lurks inside, when you pull the shift cover off, send us some pics so we can see the shift forks and their surfaces here:

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That'll help us see what's what to an extent... at least whether it was really rebuilt or just cleaned up on the outside...

Hope this makes sense...
 
#82 ·
Okay, well... for starters, it's not freshly rebuilt or any time recently based on your pictures.

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The wear above on the shifter fork is pretty typical for quite a few miles or a mal-adjusted shifter that was pushing the fork into the slider while in gear (sometimes this can happen from slamming gears and bending the forks but... well... You Know what I mean..)

The discoloration of the yellow/gold (below) of the synchro rings is from a non GL-4 gear oil and most likely, a GL-5 was used instead which probably won't cause any issues by discoloring, but it's likely the wrong gear oil in there from the get go.
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Sliders look to have some wear on them too but, this is typical for quite a few thousand miles on a transmission of this age. Not sure what else I can say as I don't have more pictures but I would question the validity of any rebuild recently or within a few thousand miles... Definitely not a rebuild of any recent occurrence...

Gears have some rust staining and wear on them but it's hard to tell if it's actually wear or debris. I would place it in each gear by hand (manually sliding the sliders back and forth and rotating the input shaft (27 spline :p ) to carefully examine every tooth visible to your eyes and take pictures of anything suspect.

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Not trying to be a Debbie-Downer, just citing facts here and evidence on an information-gathering inspection of what we can see from pictures provided.

Hope I don't come across as an *%(^$@#... Not meant to be anything but helpful :)

~Andy
 
#83 ·
Thanks.Not at all brother. This trans wasn't rebuilt, the other one was (m21) didn't get that one because of the 2.20 first gear. I'll replace the sliders and the retainer and use the GL 4 gear oil. But I'm not gonna get it rebuilt. I figure my Saginaw from 72 is holding up so I'm sure this will too.🤷‍♂️
 
#84 ·
Gotcha! Sorry, totally my mistake. I don't think it looks too bad at all in that case, just a typical Muncie internally. Find the correct gear oil for that thing and it will last a long long time though. The new GL-4 oils are not all created equal. GL-4 compliant is not the same as GL-4. The Driven brand is best from what i have researched so make sure you do your homework for a long and happy life behind that engine.

Another great video from Paul:



Enjoy, friend!! :) Welcome to the Muncie family :p
 
#86 ·
Forks could work for a long long time from that condition although as cheap as they are (buy good ones from Paul or other reputable source), I would purchase two new ones for the heck of it. The less play between the groove in the sliders and the fork ends, the better. Smoother shifting, less wear, etc.
 
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