How to decode 1978 Transmission pan stamp?

[Charlie P.]

The transmission pan on my '78 has a stamp on the passenger side, either 38B16D or 88B16D. Car was built Feb. 25, 1978. Transmission serial number on the driver side housing matches correctly. Pics of both numbers attached. The JG does not mention either number. My guess on the pan stamp is 8=1978; B=February 16=day of month D=shift. That leaves the first digit unaccounted for (or possibly the second, if the first two are 88).

Can anyone advise/confirm how to read this stamp?

Thanks,
Charlie

[Tom R.]

Re: How to decode 1978 Transmission pan stamp?

The transmission pan on my '78 has a stamp on the passenger side, either 38B16D or 88B16D. Car was built Feb. 25, 1978. Transmission serial number on the driver side housing matches correctly. Pics of both numbers attached. The JG does not mention either number. My guess on the pan stamp is 8=1978; B=February 16=day of month D=shift. That leaves the first digit unaccounted for (or possibly the second, if the first two are 88).

Can anyone advise/confirm how to read this stamp?

Charlie, you're assuming its a date code but I would guess the first digit as a "3" rather than an "8". I've not caught this before but I'll have to check my 78...maybe we can figure something out.

[David B.]

Re: How to decode 1978 Transmission pan stamp?

The production code number stamped on the right side of the trans oil pan includes the source, year, month, day, and shift produced. The first letter is the source code. B = Parma 350, 8 = year, B = Feb., 16 = Day of month, D = 1st shift
Chevrolet printed a loose leaf manual called "Product Identification Manual" which helped Dealers identify almost every trans part etc. etc.. It also explains the code for a multitude of parts besides the trans.

[Charlie P.]

Re: How to decode 1978 Transmission pan stamp?

Thanks David. I had not heard of the Product Identification Manual, but it sounds like a super reference source.
Tom- let me know if you find the stamp on yours.
Charlie