I just pulled my trans to rebuild and am having trouble identifying it. Can someone help, maybe I just didn't find the right number stamped on it.
Here's what I have: S18310, 3831707, 3088336, and 3851325. I know some of those have to do with the VIN. The trans is not original to the vehicle which is a '69 GTO.

I just pulled my trans to rebuild and am having trouble identifying it. Can someone help, maybe I just didn't find the right number stamped on it.
Here's what I have: S18310, 3831707, 3088336, and 3851325. I know some of those have to do with the VIN. The trans is not original to the vehicle which is a '69 GTO.

You need to look on the top of the Transmission by the top ear.
It has a number stamped in it.
It's the vin
Should start with a P

Usually I'm found working on my Pontiac. If you want to find me Look for the white picket fence and all the old Pontiacs parked outside. And the half dissembled engine sprawled all over the driveway!
http://www.sensible-net.com/kevin/plates/wagoon.jpg

OK, so how about this number......P40106?

Better!
P is for Pontiac.
The numbers if original are in your vin.
Now, check for a date code on the Transmission.
Also how many if any rings are on the input shaft on the front.

Usually I'm found working on my Pontiac. If you want to find me Look for the white picket fence and all the old Pontiacs parked outside. And the half dissembled engine sprawled all over the driveway!
http://www.sensible-net.com/kevin/plates/wagoon.jpg

When I was trying to determine my transmission etc. I asked in this post.

http://forums.performanceyears.com/g...152#9126066152

Your may want to try that but you mentioned yours is from another vechicle. Do you know if it's a TH350 or TH400?

Here's is a copy and paste from the above link.
Goathead68, good info, but one error. The partial VIN used on the engine and transmission starts with "2", which means "Pontiac". What they actually used was the VIN minus the four-digit model and body style numbers.

242379B100001 would be a 69 GTO coupe.
2 = Pontiac
42 = GTO (model)
37 = coupe (style)
9 = 1969 model year
B = assembly plant
1 = V8 engine
00001 = build sequence number

So what you're looking for is the VIN minus the "4237", and it would look like this:
29B100001


** I found my tranny vin right by shifter linkage boot. As per pic below

->KB<-

No, the transmission is not original to the car. P=Muncie transmission, never seen the date code stamped like this and I'm assuming the 4 is the year with the 0106 being Jan. 6. http://www.5speeds.com/casting.html

Too easy..."325" is last 3 digits to the '64-early '65 muncie 4 spd case.

This is the case that takes the small (7/8") cluster pin & early (weak) gearset. In the past, to upgrade these early Muncies, have pulled what was left of the typical 2.56 wide ratio gearset & have gone back with 2.52 or 2.20 late '65 & later gearset. Usually the "325" case has suffered pin stretch in the front hole. By machining to accept 1" pin, egged out hole goes bye-bye. In performing this mod, rear hole of the "325" case has to be machined on a taper.