C2 (66) Transmission identification

[John H.]

Re: C2 (1966) Transmission identification

Anyone know anything about those casting numbers on the side of the case?

Ron -

Most likely they're foundry pattern identifiers.

[Wayne M.]

Re: C2 (1966) Transmission identification

Anyone know anything about those casting numbers on the side of the case?

Ron here's 2 pics of 1966 Muncies, both M21, about 3 weeks apart in assembly. The P0211 is from Corvette # 140xx. The other P0308 has the VIN obliterated.

On the earlier one, notice the upside-down "1" with the 4 dots above it; means this case was cast the 4th week of January (1966); and it was assembled on the 11th of February.

On the later-dated case, notice the right-side-up number 2 with the 3 dots under. Again, cast the 3rd week of Feb and assembled March 8th. The large number 9 and number 4 (respectively) are probably as John H. has mentioned. I've seen as high as a large "13" on some '69-up cases.

If you look real closely, there's a bunch of other light scribblings/scratchings in the casting; probably meant something to someone way back.

[Ronald L.]

Re: C2 (66) Transmission identification

Thanks guys, I have been focusing on 5010 cases specifically, and have noticed as the model got older in late 67 production the numbers were rougher. And they certainly have a lot of scribblings, from the people that inspected the sand cast mold before it rotated into the pour part of the foundry. The early ones had very little of that it seems to get worse towards the end of the 5010 run.

Wayne, how would you read an upside down 2 with 5 dots above it?

[Larry T.]

Re: C2 (66) Transmission identification

What is the closest to the production date of the car you would expect to see a transmission date? i.e., if you had the P01005 (Oct. 5) tranny, and an Oct 8 build date is that too close or is it very possible?

[Ronald L.]

Re: C2 (66) Transmission identification

Larry,

From 66 5010 data only, the range varies in the time of the year as well but nothing that close. The range I have is 18 to 47 days, where the high number crossed the new year. I do not remember what year it was, seems like in that time frame the union got the time off between Christmas and the New Year. John probably knows...

[Wayne M.]

Re: C2 (66) Transmission identification

.... how would you read an upside down 2 with 5 dots above it?

Ron, I've seen 5 dots and I think it happens when the first of a (say) 31-day month falls on a Monday or Tuesday; then the Wednesday thru Friday or Saturday of the end of the month would get the 5 dots.

[Ronald L.]

Re: C2 (66) Transmission identification

Wayne -
5 dots on a upside down 2. Feb 1966. Does this pass reason. Feb 28, a Monday was the last day of that month, and if this is how it was counted makes sense...

Week 1 - Tuesday was the First date of February, h'mm not sure on this one
Week 2 - Monday = 7, wk 3 = 14, wk 4 = 21.

Your thoughts?

[Wayne M.]

Re: C2 (66) Transmission identification

Wayne -
5 dots on a upside down 2. Feb 1966. Does this pass reason. Feb 28, a Monday was the last day of that month, and if this is how it was counted makes sense...

Week 1 - Tuesday was the First date of February, h'mm not sure on this one
Week 2 - Monday = 7, wk 3 = 14, wk 4 = 21.

Your thoughts?

I did this with my 1966 calender before my eyes, and yes, I think the way you are looking at it makes sense. For the month of JANUARY, as the 1st was on a Saturday, then Monday 3rd would have had the digit 1 and one dot. And Monday 31st Jan would have been the only day to have 5 dots. Then, on Tuesday 1st Feb, the digit would increase to 2, with one dot, etc, ending the month on Monday 28th (the only day in that month with 5 dots).

[Cecil L.]

Re: C2 (66) Transmission identification

Looks like the stamping error was corrected before Oct. 18 as my original M-21 was stamped P1018. L-72 #5664.

[John H.]

Re: C2 (66) Transmission identification

I do not remember what year it was, seems like in that time frame the union got the time off between Christmas and the New Year. John probably knows...

As I recall, the "holiday week" from Christmas Eve through New Year's Day didn't get negotiated into the UAW contract until the very late 60's or early 70's.

[Eric D.]

Re: C2 (66) Transmission identification

I check thru all my 1966 Muncie cases(about 50) and I have
P01012 and P01014
I also have a 1965 case P01102

Hope this helps... Crash

[Ronald L.]

Re: C2 (66) Transmission identification

John - Wayne -

I'd guess it was the protracted strike of 1970 that the vacation time got in the mix for sure.

[Ronald L.]

Re: C2 (66) Transmission identification

Hey guys - any thoughts on this P date stamping anomoly?

P04220?

[Ronald L.]

Re: C2 (66) Transmission identification

Back up, anyone seen a Muncie stamp like this?

[John B.]

Re: C2 (66) Transmission identification

My 1966 Corvette (#6S102482) has a build date of October 7, 1965 with a transmission build date of P01002. This is another mis-stamp like those above; however, P01002 corresponds to a Saturday which raises some interesting questions. The case is the correct 3885010 case, with a cast date of the 2d week in June.

Here's photos of my stampings. I think they may be legitimate as there seem to be quite a few stampings like this in the October 1965 timeframe. Please tell me if you think otherwise.

BTW there is also there is another thread entitled "Muncie Build (Assy) Date Code" from August 2020 which mentions a P01001 date code.

trans 1a.jpg

trans 7.jpg