OK, After too much research, and reading hundreds of pages of online chatter, I think I have some useful information to share...
The GM 4l80e overdrive automatic transmission turns out to be a super piece of engineering. It's gone through a bunch of updates over the years, and is identified (in a sort of sloppy way in my opinion) between what most call the "Early" and "Late" models. The early model is defined as between the years 1991 and 1993. 1994 to 1996 models are considered a group on their own, and anything 1997 on is considered the later model (some even say the 1995 on is the later model).
The biggest changes in my opinion that you need to concern yourself with are things like electrical changes, cooler line placement and ECM compatibility:
In 1993 the outside connector and internal wiring harness was changed. This would require modifications to your harness.
In 1994 the electronics where updated, specifically the PWM force motor carrier frequency was changed from 292.5 HZ (earlier model) to 614 HZ. This would require a ECM change.
In 1997 the cooling line hook-up was changed moving the return line more toward the center of the transmission for improved lubrication. This would require some reworking of your cooler lines.
There are a bunch of other updates, but the ones I mention above are in my opinion the most important when considering using this transmission. So...
I found some not so reliable chatter about using the serial number on the metal ID tag to date this transmission. Not reliable because there seems to be several opinions on what these magical numbers mean. Plus I found talk about how some rebuilders would change the serial number to reflect the date the transmission was rebuilt.
I also stumbled across a huge list of code numbers and their corresponding models and years for both the 4l60e and 4l80e. I consider this list way more useful. This second list is copied from a forum page found here (scroll down on the page to see everything):
4l80e and 4l60e Code Numbers The list comes from some kind of subscription only service. I was unable to enter the site simply because I haven't paid the entrance fee. The site is found here:
Subscription only site... I copied and pasted the list from the forum and created a .pdf file (for my own convenience) and I'm happy to share it with anyone who wants it. All the information in the list I made is from the forum link above. I'm not sure if the StoveBolt forum will allow uploading a file, so if you want the information, just send me a pm with your email address and I can email it to you.
So what did I learn about the metal ID tag? They come in yellow, blue, and green. There is a bunch of chatter online about the green tags being put on the transmission at the time of rebuild (Goodwrench franchise does this maybe?).
I have learned that if you take the code number from the metal ID tag, drop the first and last characters, the remaining code can be used in the list to hopefully find what year and application the transmission was originally from. In my case, the code says: 04WBP7. Drop the first and last leaves 4WBP. In the list, it says this transmission came out of a 2004 Izusu Workhorse, NPR, Tilt Cab box truck. This makes sense because the guy I bought the transmission from says he was told it came from some kind of box truck.
I hope this proves to be useful to others.
Thanks and take care.
