GM Date codes?

[Charles M.]

On some parts "A" designates January. Does that hold true on everything or are there some pieces where the date coding sequence begins in Sept when the model year was generally first available to the public?

[Jack H.]

Re: GM Date codes?

Some items date from the start of model year production (A, B, C....) while others are based on calendar year. Generally, those where the date code sequence was stamped on the part vs. those where code sequence was embossed skip use of the letter 'I' in the sequence (can be confused with the digit '1'). When in doubt as to which sequence applies to a given item, consult your copy of the NCRS Judging Guide book--most critical part dating is re-defined on a component by component basis.

[Joe L.]

Re: GM Date codes?

Chuck-----

There are exceptions. Transmission date coding is usually by model year. Trim plate VIN coding is by model year. Those are 2 that come to mind right away. There may be a few others. For the most part, "A"= January and months follow sequential alpha characters (when an alpha-numeric date coding system is used).

[Joe L.]

Correction

Trim plate DATE CODING is by model year. There is no VIN number on any trim plate.