Thread: Transmission ID

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Can you guys help me ID these boxes. They are advertised as T-10 4 speed, but on the phone he described them as Muncie, M-20. One steel, the other aluminum.

Thanks, Rad

Hey Rad:

I believe these are Muncie transmissions. Couple things to look for:

Muncie transmissions have 7 bolts on the side cover (as opposed to 9 for a T-10). Snap a picture of the other side of these bad boys and I think you'll find 7 bolts holding the covers. Muncies can be differentiated from Saginaws as the the Muncie reverse lever is in the extension and the Saginaw is in the transmission case.

As to type of Muncie:

M-20 is a wide ratio
M-21 is a close ratio
M-22 is a heavy duty close ratio, also known as a "rock crusher"

Hope this helps,
Glenn

the trans on the right is a muncie from a corvette it has the speedo on the pass side everything else is on the driver side. ted

Good catch, Ted.

1970-74 Corvettes and Camaros had the speedo drive on the passenger side of the transmission. All others looked like the one below.

hay glen we usto tell the m20 from the m21 one had a grove cut in the input shaft but I cant remember witch is witch any more getting old I guess maybe you remember..ted

Oh man.. This is a stretch, but as here's a copy of some old hand written notes..

Muncie M-20 Wide Ratio No groove 2.56, 1.91, 1.48, 1.00
Muncie M-21 Close Ratio 1 groove 2.20, 1.64, 1.28, 1.00
Muncie M-22 Rock Crusher 1 groove 2.20, 1.64, 1.28, 1.00
Muncie M-20 / M-21 Special Order 2 grooves 2.52, 1.88, 1.46, 1.00

I'm fairly sure the wide ratio (M-20) did not have a groove on the input shaft in it's stock form, but they have been known to be replaced.

I think the "Special Order" were available in early (1963-65 Biscayne with the 409 only?)

The M-22 is easily identified once you open is as the gear teeth are beefier. The M-22 was only produced in a close-ratio version. If anyone says they have a wide ration rock crusher, they are "mistaken".

The input shaft and cluster gear are different on the M-20 and M-21.

The input shaft, cluster gear, 1st, 2nd, 3rd and reverse idler gear are different between the M-20/21 and the M-22.

Everything else will interchange. Synchro rings from newer years will work in older years but not the other way around so they should be changed as a package.

Good thing I wrote this stuff down - I'd never have remembered it! I think I kinda smell some heavy gear oil?

Regards All,
Glenn

Thanks for the great info. I was able to id the trans as a 1970 M-20 with the two grove input shaft and 2.52 first gear ratio, which will be perfect behind the 283 in my 57 Chevy.

Bad news: Broken teeth on input and cluster gears.
Good news: Got it for $50.

Now I'm finding out that the input is $313 and cluster $360! Bearing kit $225.

So, now I am looking for parts. Help!!

D and L Transmission seems to stock a good supply of Muncie parts had prices that are less than what you’ve got so you may want to shop around a bit and just call these guys. 1-631-351-4837

http://www.dandltransmission.com/muncie.html

Specifically:
Gear, cluster (counter), Muncie 1" M-20 wide 25-22-19-17 made in Italy $192.00
Gear, cluster (counter), Muncie 1" M-20 wide 25-22-19-17 excellent quality, made in Asia $148.00

Gear, input (main drive), Muncie wide 21T 10 spline (66-70) $152.50
Gear, input (main drive), Muncie wide 21T 10 spline (66-70) made in Asia $118.00

It may be that the prices you have are for OEM US made components. There are some pretty good deals on the Italian and Asian replacements and if after talking to these guys you feel like they’ll stand behind the import parts, they’ll probably hold up just fine behind your 283 in the '57.

TB Transmission also has a good web site and a good selection of parts. 800-425-4226

http://www.tbtrans.com/muncie_4_speed.htm

I have not done business with either of these firms, perhaps others will chime in.

A quality rebuilt M-20 is worth, in my opinion, $1,000 – 1,200. Good used will set you back $750. A Super T-10 replacement from Richmond Gear is over $1,500 so you need to decide if rebuilding your $50.00 find is worth it – I’d go for it – if for no other reason than it’s keeping a piece of hot rod history intact and will give you a great sense of pride when you finish!

Bear in mind that this is complex process and the first time is very time consuming. Get a book that shows detailed illustrated parts breakdowns of each step and take your time. Make sure all your pieces are really clean and use lots of lint free rags and wipe everything off (especially your hands) to make sure you have nice clean, good surfaces to hold as you assemble. If you have a well ventilated are to work in, Acetone is a good solvent for this type of work. A book will also give you some tips in reference to order of assembly that are critical for a proper rebuild. Everything should be butter smooth when your done and the assemblies have to spin without any “rough spots”.

Let us know what you decide and take some pictures for us to enjoy your progress. Have fun with this!

Regards,
Glenn

Thanks so much. The people on this forum have been so helpful.

The Muncie, W/4 on the floor Hurst shifter, was the thing in my day. Auto trannys are fine, but since this car has three pedals already - well, I know what I have to do. I would like to do the rebuild myself, so, perhaps someone knows of a good book for a guy like me. I'm pretty mechanically adept, but just have never done a manual or auto trans before. Other than not buying American, I have no problem with euro or asia parts. This car will not be seeing huge torque anyway. After all, it will retain the stock 57 rear, and I don't want to change that out.

Thanks again for the tips. Rad

Rad -
Here's a few links that have what you need..

http://www.classicchevycluboftucson....ics/muncie.pdf (this is a freebie and really worth reading)

http://camaro_obsession.tripod.com/exploded.htm

http://carburetor-manual.com/muncie-...975-p-136.html

OK, you have talked me into this. Thanks for the support and confidence. Those articles are invaluable! I'll keep you posted.

Rad