4-speed Muncie trans

[COPO_Anders]

Hi,
A friend of mine bought this 68 Chevelle recently and is having trouble with the 4-speed in it. Does he have to get it out of the car to determine which trans he has, M20,M21 or M22? He wants to find a replacement first and then take it into the shop.
Stamped on the trans he found: P8E23 and 18W348416
Any help is appreciated.

http://www.yenko.net/ubbthreads/pics/usergals/2015/05/full-666-25704-20150314_151124.jpg

[scuncio]

Muncie from a 1968 Nova. I don't believe you can tell M20/21/22 in '68 unless you pull the trans and count the grooves on the input shaft (2=M20, 1=M21, 0=M22)

[SuperNovaSS]

You could also pull the side cover if you don't want to pull the whole trans.

Jason

[earntaz]

Drain plug?

[hiperf406]

The M22 has the drain plug in the bottom of the transmission, don't believe 20 & 21 have a drain plug - only the fill plug in the right side.

[earntaz]

Exactly ... so that bit of info would thin the herd.

[L78racer]

a little bit of work but he could put it on jacks, pull the plugs and crank the engine over by hand in first gear and see how many revs it takes to get the driveshaft to go one full turn.

[Verne_Frantz]

You can try this method. Drive the car in 4th gear at 1000rpm and note the the speed. Now drive it the same speed in first gear and read the tach. If it's about 2200rpm, it's a close ratio. If it's about 2500rpm, it's a wide ratio.

Verne <<GRAEMLIN_URL>>/biggthumpup.gif

[scuncio]

I like Verne's method! Why didn't I think of that.

[SuperNovaSS]

Good call Verne. What I am curious about if he is having trouble with the trans, why doesn't he just pull it and have it gone through? There are lots of guys that are comfortable building Muncies. They are pretty simple.

Jason

[earntaz]

Jason -- X2 ... Geez, where's my piece of broom handle for the installing the cluster? LOL

[COPO_Anders]

Yes Verne, that´s a good method ! I´m guessing it´s a wide ratio, but we´ll try that and see what we find. I´ll get back with the result. Thank´s all !

<<GRAEMLIN_URL>>/youguysrock.gif

[WILMASBOYL78]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: scuncio</div><div class="ubbcode-body">Muncie from a 1968 Nova. I don't believe you can tell M20/21/22 in '68 unless you pull the trans and count the grooves on the input shaft (2=M20, 1=M21, 0=M22) </div></div>

M22 will have the drain plug...build date makes it a possible BB application. They didn't start using the A,B,C codes until fall of 68 [69 models]..Nova Muncie 4 speeds are rare...might have some value to a Nova guy looking for a dated part.

wilma

[Salvatore]

Pull the trans and fix it COPO.
Better yet, put a Jerico in it or a Nash 4+1.
By the time you guys figure out what trans it is you can have it out.

And we sent all our good old Pro Stock cars to Sweden. GEEZE!

(:&gt;

[SS427]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WILMASBOYL78</div><div class="ubbcode-body"> Nova Muncie 4 speeds are rare...might have some value to a Nova guy looking for a dated part.

wilma </div></div>

Like this one......came to me in an LS6. Needless to say I replaced it with the correct part and bought this one for my inventory.

I should add, don't always assume that a trans is an M22 based on the drain plug and/or stampings. You can always put M20-M21 guts in an M22 case. Also, I believe starting in 1970 all Muncie 4 speed cases were drilled for drain plugs.

[COPO_Anders]

He didn´t get back to me right away. Apparently he did make the Verne-test and found out that it was a M-20. He has pulled the trans and is going on a 150 mile trip to a guy who knows Muncie´s inside and out, as we don´t know of any Muncie guys locally. I think he said that guy is around 75 now.

<<GRAEMLIN_URL>>/3gears.gif

[Verne_Frantz]

I like the wide ratios very much. You can run a higher rear gear for lower rpm at highway speeds and still have an easy launch without riding the clutch.

Verne <<GRAEMLIN_URL>>/biggthumpup.gif

[300deluxeL79]

don't assume a drain plug confirms it's an M22, i've added drain plugs to a few M20-21s i had apart. <<GRAEMLIN_URL>>/rolleyes.gif