From time to time someone asks how to verify an engine is original. I don't remember ever seeing it mentioned here, but transmissions are stamped with the serial number also. Today I went looking for the serial on the 700R4 in my 91 Formula. The service manuals show a few possible locations for ID stamps on the 700R4. There's a flat pad on the passengers side just above the inspection cover, and another further back above the pan rail. The one just above the rail had some stamps, identifying the build date of the 700R4. I found the serial number further back on the case, on the drivers side just in front of the tail housing. The 6 digit number matches the last 6 digits of the VIN on the car. I was kind of hoping the transmission wouldn't be original so I could easily justify the T56 swap... No such luck.

The T5 would have an ID tag on one of the main case to tail housing bolts, but the partial VIN should appear on the flat pad on the passengers side of the main case. The shop manual for 1991 shows an alternate location on the drivers side of the main case.

 

interesting I never knew trannies where stamped with matching serial numbers I learn something new everyday

 

Drew - are the serial numbers on a piece of the case that looks like a 3D rectangle casted into the case - and the numbers are running up and down, perpendicular to the ground?

 

Mine was vertical on the flange just in front of the tail housing.

 

Get this,
When I rebuilt my transmission in 1998, there was no VIN, no stampings, no nothing, there was a place for it, but it was all blank...

I figured it had been replaced with a new trans as when I rebuilt it the innards were perfectly new looking. The previous owner only had it for 6K miles before he parked it. He got it off of a small dealership who got it from the first owner.

In 2007 I fried 3-4 and the trans guy made me a shift kit of his own design, more or less he said there was no performance parts in the trans it was the least performance trans that they made... He changed that.

MX0 was cast in the housing and that was it.

John

 

Are rear axles stamped as well?

Numbers matching to me always meant engine/tranny/rear.

 

They're supposed to be stamped on the front of the passengers side axle tube... But I'm not sure if the car's serial number is stamped there, or how visible it'll be. Most rear axles weren't painted, they were left bare steel so they usually get pretty corroded. I've never been able to spot the code, but I usually don't bother to look for it either.

 

No I do not believe that they were on the axle. My 1989 Convertible was really clean, it still had the original stickers and even a sticker that looked like a price tag sticker on it. There was no numbers that would reference the VIN that I found.

 

The book says there's a stamp or a tag on one of the bolts.. But all they tell you is manufacturer, build date, shift, etc... No mention of a serial number.