NCRS Spec Guide For Muncie ID #'s

[Patrick T.]

I've been sitting on this one for a couple months, but it's time to face the music. The unit serial number identification section in the Spec guide seems a little confusing to me regarding the ID of my particular transmission.

My '67 Muncie has a main case #3885010, which is a 63-67, and a casting date of 7-1. There is also a beat up copper tag attached to the linkage housing cover which is #3880853, which from what I know is a '67#. So far, so good.

The problem that I see is with the vertical number stamped on the front part of the main case, which identifies the manufacture date and location, Toledo or Muncie, Indiana. This number seems to be P7P23, which the way I read it would be September 23, 1967, a '68 number, which is a bummer, since the car was built around July 15, 1967. Am I reading the Spec Guide correctly? Can anyone straighten me out on this, I can take it, it's almost Friday. Thanks. Patrick

[Mark J.]

Re: NCRS Spec Guide For Muncie ID #'s

I've got the same trannie in my '66. If I remember correctly, the date stamp matched the casting date on my engine block. Also the car's serial number is stamped vertically on the front of the case on the passenger side.

Mark

[Joe L.]

Re: NCRS Spec Guide For Muncie ID #'s

Patrick----

The year on transmission date codes refers to the MODEL YEAR of the vehicle that the transmission was originally intended for, NOT necessarily the year that the transmission was built. So, if your code is actually P7P23, that would be a Muncie transmission built on September 23, 1966 for installation in a 1967 model year vehicle. That code would seem too EARLY for a car built on or about July 15, 1967.

[Bill Clupper]

Re: NCRS Spec Guide For Muncie ID #'s

Patrick, if you are fortunate enough to have the protecto-plate, the Trans ID number is carried on the plate. You could match it to your car. Also, as mentioned, the car's VIN (same as on engine) will be stamped on the case of an original '67 Corvette case. Pass car cases are usually spamped with a vin also, but often on the top of the case, renderinf them almost impossible to read with the body on. The 010 case was only used '66-67 FYI.

[Patrick T.]

I Still Don't Get It

Pardon my ignorance, but you guys still have me baffled. Where is the cars VIN stamped on the transmission? I have P7P23 stamped on the case. I just can't seem make a connection with my VIN # of 22---. The engine stamp does match the VIN, but where would the ID of #22--- be on the transmission?

Could you please simplify this into "Muncies for Dummies"? Thanks. Patrick

[Wayne M.]

Re: I Still Don't Get It

Patrick --- The trans VIN derivative should be found exactly on the opposite (drivers) side of the case from the P7P23 (on the case flange where it mates with the tail case). It also is stamped vertically; sometimes you have to look carefully, as the surface of the casting can be quite rough.

[Mark J.]

Re: I Still Don't Get It

Patrick

The Muncie date is stamped vertically on the driver's side flange next to the bell housing. The car's serial number (VIN) number is stamped vertically on the Passenger's side flange next to the bellhousing. Also, you said you date stamp was P7P23. You might want to reinspect the stamp as the second P is the 16 letter in the alphabet, which doesn't match up to a 12 month calendar. if the second letter was F, ie "P7F23", then you would have the July date you are looking for.

Mark

[Joe L.]

Re: I Still Don't Get It

Mark-----

Muncie transmission month build codes don't follow a normal progressive alphabetic sequence. Several letters are NOT used, including "F". "P" is the character assigned to September-built transmissions. And, no, I don't know why.

[Mark J.]

Re: I Still Don't Get It

My error, you are correct. Beginning with January, the codes are A,B,C,D,E,H,K,M,P,R,S,T. P is indeed September.

Mark

[Dave - NCRS#24235]

Muncie stamps are everywhere?

Reading this thread is confusing, or the stamp marks are randomly located on Muncie transmissions, if they appear at all. - Dave

[Jeff]

Re: I Still Don't Get It

Many (actually most that I am familiar with) manufactureres eliminate the 'mistakable' letters from the sequence. For example, almost no one uses I and J since they are so easily mistakable for each other, in fact, I think I remember from H.S. Latin that they were once even the same letter of the alphabet, not seperate.

Often E, F and/or P are not all used, C, O and Q are not all used, etc. Depending upon which the particular manufacturer chooses to eliminate (or is not even supplied with by the stamp manufacturer) you can get pretty deep into the alphabet and get P as September.

JP

[Joe L.]

Re: Muncie stamps are everywhere?

Dave----

Well, the easiest way to look at it might be this way: there are a maximum of only TWO STAMPED-IN sets of numbers on a Muncie transmission. Both are located on the transmission main case which really isn't all that large of a thing to examine. One set of numbers will begin with a "P" and that's the transmission source/production code. The other set of numbers, if present(SERVICE transmissions never had them), will be the VIN-derivative.

[Joe L.]

Re: I Still Don't Get It

Jeff----

I agree. However, the puzzling thing here is that in virtually every other case, GM uses the normal alphabetic sequence when using a letter to denote a calendar month. They even do this in the case of CASTING numbers which are the most easily confused characters of all. But, in the case of transmissions only, they use this more arcane system.

[Patrick T.]

NOW I Got It !!!!

I just checked the transmission again on the drivers side, right up next to the bell housing, and sure enough, there was stamped my exact VIN (7S122---). Very easy to read. The case or dates have never been tampered with. I know I've seen it many times, but just past over it to find the P7P23, which still doesn't make sense, but now it's a moot point.

There's no use in worrying about what the P7P23 stands for. After reading all of your posts, it seems the exact interpretation of what this number signifies is very debateable, although I don't think it's worth the effort.

My feeling is the VIN number has a lot more creditability given the fact that it's so easy to identify with the rest of the car. Thanks to everyone for your help. Patrick

[Mark J.]

Re: NOW I Got It !!!!

Excellent! Let's see...there were 22,940 '67 Corvettes. The serial number on your trannie is 7S122--- and your date is September 23rd. You must have one of the last ones produced. Interesting.....

Mark