66 m-22

[Anthony P.]

Re: 66 m-22

I have a question concerning the tag on a Muncie trans, is it just a part # tag? I ask because the vin is stamped, the asm date is stamped. so the tag indicates what?

[Joe L.]

Re: 66 m-22

I have a question concerning the tag on a Muncie trans, is it just a part # tag? I ask because the vin is stamped, the asm date is stamped. so the tag indicates what?

Anthony------


The metal tag identifies the GM part number for the transmission assembly.

[Anthony P.]

Re: 66 m-22

Thanks Joe, I though it might be Mine reads 3870354 what does that tell you?

[Joe L.]

Re: 66 m-22

Thanks Joe, I though it might be Mine reads 3870354 what does that tell you?

Anthony------


It's a 1966-67 M-20. This particular part number was used only in PRODUCTION and was never available in SERVICE.

[Anthony P.]

Re: 66 m-22

Anthony------


It's a 1966-67 M-20. This particular part number was used only in PRODUCTION and was never available in SERVICE.

Thanks again, that's good to know!

[Larry E.]

Re: 66 m-22

Steve------


I'd be amazed if any dealer would still have 50 year old records. Even small-town dealers that stay under the same ownership for 50 years won't keep records for that long.

If you can find the "Lender of the $$" if it is not GMAC;you may have a chance of finding the Wholesale Invoice. Some small banks keep records for a very long time. Larry P.S. Of course one has to have somewhat of a contact with the bank (relative;original owner contact&etc.) to get permission to do the search.

[Wayne M.]

Re: 66 m-22

..... Does the transmission have a drain plug AND does that drain plug appear to be original to the transmission (e.g. do the fill plug and drain plug appear identical?)

I would add the style of the magnetic plugs. I believe from the beginning of M22's the plugs on the left were used (both fill & drain).



c

[Patrick B.]

Re: 66 m-22

I think 66 and 67 Muncie cases had a magnet made into the case and may not have used magnetic plugs.

[Joe L.]

Re: 66 m-22

I think 66 and 67 Muncie cases had a magnet made into the case and may not have used magnetic plugs.

Patrick-------


Yes, even later Muncies had the internal magnet which was epoxied to the bottom of the main case. However, M-22's used the magnetic plugs as Wayne pictured.

[Douglas L.]

Re: 66 m-22

I have a question concerning the tag on a Muncie trans, is it just a part # tag? I ask because the vin is stamped, the asm date is stamped. so the tag indicates what?

To add to what Joe said. As I understand it, the tag, other than denoting whether or not it was a m20/m21/m22 also has to do with what rear gears the car it was going into was equipped with. More specifically, what speedo drive gear was installed in the transmission. Certain ranges of rear gears would use a specific speedo driven gear which would only work with a specific drive gear. E.g. 2.73 to 3.36 used a particular drive gear while 3.55 to 4.11 used a different drive gear and 4.56 another one. Since the transmissions were delivered from Muncie to St. Louis with the drive gear installed the tag told the assembly line which trans to use for each application.

[Larry E.]

Re: 66 m-22

831.JPGFWIW: I thought I have seen the following top plug on M22's. Could have been in Al's class or Colvin's books. Comments Please. Larry

[Joe L.]

Re: 66 m-22

[ATTACH=CONFIG]65622[/ATTACH]FWIW: I thought I have seen the following top plug on M22's. Could have been in Al's class or Colvin's books. Comments Please. Larry

Larry-------


I don't think this is a magnetic plug. However, I suppose it's possible that a non-magnetic plug was used for the fill plug for some M-22's.

[Tom P.]

Re: 66 m-22

In the 45+yrs that I've been rebuilding 4spds (mainly Muncies), I've never seen a magnetic FILL plug. I've only seen magnetic Drain plugs.
And the T-10s that I've seen, BOTH plugs are NON magnetic.
Of all the 63-69 Muncies I've rebuilt (except ONE), I've always removed the magnetic donut and installed a magnetic drain plug.
In my opinion, the magnetic donut presents a serious potential disaster for total destruction of the internals------------------as seen below.

This destruction was caused when the magnetic donut came loose.



This is the remains of the donut that destroyed the above Muncie, compared to a removed donut and a magnetic plug.


In my opinion, REGARDLESS of NCRS correct or not, it's not worth the risk to leave the donut in the case when doing a rebuild.

[Patrick B.]

Re: 66 m-22

I checked several transmissions I have. A 67 M-21 and a 66 M-20 both had non-magnetic drain plugs with no marking. A March 1970 M-22 had Lisle magnetic plugs like those pictured for the 661 case in both the fill and drain positions. Interestingly, the absolutely original transmission in my 1970 LT-1 (June 661 case M-21) had magnetic plugs in BOTH fill and drain positions and these plugs were marked with a "P".

[Joe L.]

Re: 66 m-22

I checked several transmissions I have. A 67 M-21 and a 66 M-20 both had non-magnetic drain plugs with no marking. A March 1970 M-22 had Lisle magnetic plugs like those pictured for the 661 case in both the fill and drain positions. Interestingly, the absolutely original transmission in my 1970 LT-1 (June 661 case M-21) had magnetic plugs in BOTH fill and drain positions and these plugs were marked with a "P".

Patrick-------

1966-69 Muncie M-20 and M-21 were not originally manufactured with drain plugs. So, if you had some with drain plugs, someone added them. This is not difficult to do as the boss for the drain plug is present on all Muncie main cases.

All 661 main cases were originally manufactured with a drain plug.