Gmcdually

Looking at a car that claims to be all original the vin on engine matches Vin but trans is one number off in sequence. Owner claims this must have been done at factory?

Boiler_81

Likely an error at the factory. This is not all that uncommon. The line workers were suppose to increment the stamp for every car. Sometimes they forgot.

Gmcdually

Thanks for reply . Would this mean there are two
Transmissions with same vin out there. Would
This still be considered matching numbers ?

joe_padavano

Clearly they don't match. Without proof that it was a factory error, it's just a story. I've heard far too many stories over the years. Is it likely a mistake? Yeah. These cars were built by assembly line workers whose sole job was to kick them out the door as quickly as possible. Little did these people realize that 50 years later archeologists would be scrutinizing their work and that tens of thousands of dollars would hang in the balance...

wr1970

I am going to agree with Joe P. X1

BangScreech4-4-2

Ahh, close enough for rock 'n' roll.

Diego

My friend has a Pontiac GT-37 with an engine that's 1 number off the VIN - it happens.

halfmoontrail

Interesting story. At least for Corvettes, the exact same die gang was used to stamp the engine and trans (probably same worker, BAM BAM), I would expect the same for other lines.


I think it is also theoretically possible (likely?) for multiple engines and transmissions in a given year to share the same VIN derivative, born in different models, because VIN derivative doesn't include body style.


Just my opinions, Steve

joe_padavano

I would expect this to be true for all car lines, as the VIN derivative stamp must have been stamped when the engine and trans were dropped into the chassis. Of course, it's also possible that the worker stamped the first one, say the trans, then realized that he had forgotten to increment the sequence number and changed it before stamping the second. These are humans, so I have to believe this is possible.

The VIN derivative stamp is unlikely to be the same on multiple engines and transmissions. First, at Olds anyway, the six digit sequence number was not repeated across model lines. The VIN tags were procured in sets with sequential blocks of sequence numbers, only the second through fifth characters (model line and body style) were not pre-stamped. That means that each six-character sequence number was only used on one vehicle per assembly plant. Yes, the sequence numbers were repeated at each assembly plant, but then the third character of the VIN derivative would be different. The sequence numbers were reused each model year, but then the second character of the VIN derivative would be different. And of course the sequence numbers were duplicated by other divisions, but then the first character of the VIN derivative would be different. Bottom line is that I don't see a scenario where two different engines could ever have exactly the same VIN derivative stamp.

Boiler_81

I also dabble in the Corvette restoration world. There have been several cases where cars have the incorrect stamp. It is usually one number off. There was a grind out procedure which was used for repair of incorrect stampings at the Corvette plant in St Louis. You can imagine the heart burn it causes the Corvette crowd when they come across a VIN which was ground and restamped.

Given the case above, the most likely explanation is a mis stamp at the assembly plant. The odds of the transmission being replaced with one with a VIN which is one unit off from the production car later in life is astronomical. If I were looking to buy the car, I would have no issue with the transmission VIN being off by one.

Gmcdually

Thanks all for the help. With a little better understanding. I also believe with only one number off and in sequence had to be done at factory. The chances of finding that trans would be nearly impossible . Story ? Maybe ,but I guess in the end it all depends who you talk with , and we all must form are own conclusions , may they be right or wrong or ever verified for sure.