Muncie M21 Transmission: P7K07 assm date, 1968 replacement #3925660 case casting

[mgreenz]

I'm not sure what to make of this transmission's assembly date code. Decoding it is straight forward enough but, as I understand it, the 660 case was introduced for the '68 MY. Is it possible that this transmission was assembled July 7th for a '67 MY car as indicated, perhaps as a warrantee replacement, or is more likely that either the assembly date code is an error or re-stamp?


I'm wondering if there are any other examples similar to this or if anyone has opinions on the authenticity of the assembly date code.


Thanks for any input your able to provide.

[mgreenz]

Here's another date code photo.

[cook_dw]

Hate to say it but to me it appears to be a restamp.  But wait on the experts.

[bcmiller]

Could be ok. Maybe. Try to get a better pic. Does it have a partial VIN anywhere?

[mgreenz]

Here are better assembly code photos, I hope.
I didn't find a vin or any other stamping on the case although its possible there
could be something on top that wasn't accessible using a mirror.

[169INDY]

Is this a Van Nyes Car ?, Los "was known" for stamping the TOP of the trans with the VIN derivative., sometimes twice
others can confirm,,,,,,

http://www.camaros.org/drivetrain.shtml#PartialVINs


added link Rev 1

[bcmiller]

I will check my pics later today or tomorrow but right now I am thinking transmission assembly date looks fine.

Yes a lot of LOS cars had the partial VIN stamp on top.

[mgreenz]

I google searched the assembly code and a picclick.com sold listing came up. The seller listed a M21 660 with an assembly code of P7K07 and no Vin.
At first I though okay here's some data to support my transmission stamp as being authentic and then it occurred to me that the transmission in the ad might be the one in my car.
Entirely possible if the transmission listing predated my cars CHP inspection report of Feb 2019.


Here's Jerry"s description of the transmission:
Transmission: P7k07 assm date, 1968 replacement #3925660 case casting, Muncie M21 4-speed, not original to this vehicle


I checked again for a vin on the case this time with the use of dum-dum. I found that I could reach from the passenger side up and over the top of the transmission and was able to press dum-dum on to the top of the case. You can see in the photo, the dum-dum test of the assembly date transferred well but I wasn't able to find a partial vin. I'm pretty confident that this transmission like the one in the picclick listing, doesn't have a partial vin stamp.


Does a Muncie 4-speed without a vin indicate that the transmission was not assembly line installed?


Thanks guys for your reply's to date.

[bcmiller]

I believe warranty transmissions (stamped CTx xxxxxx) and warranty cases (stamped CCx xxxxxx) started September 1967. Your case is dated as assembled July 7, 1967. That’s just before the warranty stampings started.

Could be the same transmission. No way to know for sure unless you can backtrack.

No way to prove that’s the original for your car.

Let me do some checking tomorrow.

[bcmiller]

Transmission assembly date stamp is fine.

[mgreenz]

Thanks Bryon.
I’m surprised to learn that 660 cases were in use prior to the 68MY.
Since this transmission has an assembly code, predates the warranty program (CT, CC stamps) and has no partial vin I suspect it was a warranty transmission or case.

[bcmiller]

Thanks Bryon.
I’m surprised to learn that 660 cases were in use prior to the 68MY.
Since this transmission has an assembly code, predates the warranty program (CT, CC stamps) and has no partial vin I suspect it was a warranty transmission or case.

They were probably doing some test castings for the upcoming model year. I don't know what the earliest they could have been, but a July 7 assembly for a 660 case would have to be about the earliest possible. I can look around to see if I have any earlier, but I doubt it.

A lot of the parts I have are dated between March of 67 and October of 67.  Just a quick look through the 20 or so cases I have here at home shows a 010 case assembled July 15 and a 660 case assembled August 23. 

I also know of a 010 case with July 26 assembly date stamp.

So likely some overlap.