Kind of a long post... I'm having trouble identifying a 4L80e core I just recently purchased for my 1953 2-Ton GMC project. A little background in case it helps:
I originally wanted to use the NV4500 5-speed manual for this project. But for reasons I haven't figured out yet, rebuildable cores in this area seem to be insanely priced. I estimated after a good quality rebuild kit and the special synthetic fluid the NV4500 needs, I would be out close to $1,500 before I had a usable transmission. That doesn't even include the costs for the bell housing, flywheel, clutch, hydraulic throw-out bearing, and all the mechanism to make it work. So I decided to try using an automatic in the project instead.
My heart doesn't completely approve, but my head has convinced me that it will be a much easier swap with the 496 big-block bolted in front of it. The overdrive will also allow me to preserve the original Eaton 1350 two-speed. I also managed to find a used but good stand alone electronic controller for the transmission as well.
So my problem is this... I don't seem to be able to date this transmission. I know that GM is typically good about marking their components so the repair industry knows what the're working with. The 4L80e has gone through several phases of improvement through the years as they flushed out reliability issues. I've been told it's important to know as much as possible before ordering a good overhaul kit. This is what I do know:
I have the later version of this transmission due to the cooler line spacing. I know it came out of some medium-duty truck due to the emergency brake drum at the tail (very helpful for my project because the Eaton 1350 two-speed has no provisions for an emergency brake). The transmission was rebuilt at some point by the Goodwrench franchise. Is it possible they changed the ID tag at rebuild?
The transmission ID tag below in the pictures kind of feels like it's the original. The tag shows a code number of: 04WB P7, and the Serial number is: 07318 089
After an exhaustive Internet search through GM transmission codes, my numbers don't seem to come up. Any one here have access to better data?
Images below. Thanks in advance for your help.
Drivers Side of Transmission Passenger Side of Transmission Evidence of Previous Rebuild Missing Bar Code Sticker from Normal Location Transmission ID Tag
