how can you tell the difference in the 4L80's?
 

I was just wondering how can you tell the different years and or what kind of vehicle a 4L80 came out of?

there is a tag on the pass side, tells what year it is-i would avoid 91-93, they had an older arrangment of the force motor
97 up moved the cooler return line to the back into the center support
i forget what year they started using a bellhousing bolt in the 12 o clock postion
if you can, pick a 99 or newer, the more fact. upgrades the better, but all will work

Great I can't even tell what that thing says but are the trans cooler lines a for sure way to tell. I was told that the pictured came out of a 02 HD is this true?

looks like a 96-back trans, def not an 02-may have come out of an 02, but not orig-if you pull the pan and look at the force motor you can tell if its 91-93-if it was used in an 02, it might be a 94-96-the 94 up sup used a diff force motor voltage or whatever and and was not compatible with the older pcm

I don't think a person would get a old style transmission to put in a new truck plus the fittings are in different places also the missing 12 o'clock bolt it just wouldn't make any sense to. :ripped: so I just have to work the channels now to get my money back for it. :bang::mad:

okay so how would I be able to tell on the pressure control (force motor) that it is a pre 94?

it has a diff plug and is a little larger-i think the plug comes off the back and is wider-i could prob snap a pic of a 94-up
is there know way to read the tag

This is the case connector on the 60/65/70 with an ISS and the one on the 80 with the later harness should have one that looks very close. The only difference is a couple of pins are moved around. The early harness looks totally different and should have a threaded hole in the middle of it for a bolt. The unit you have is definitely a 91-96 and could be earlier unit with an updated harness. Here is a picture of the case connector. Vince
http://i110.photobucket.com/albums/n...s/IMG_4535.jpg

i thought about suggesting looking at the case plug, but if it was upgraded still wouldnt tell a lot-i have a 91-93 unit that was GM remanf., bought it on the chance it was 94-96 (they replace the side id plate with a diff one)
based on the case plug, but ended up being older w/upgraded harness
it was only $75, lol-it was a 4WD unit, but had the speed sen ring, i was gonna convert it to 2WD for a spare

on the force motors, the old one 91-93 will have a plug on the back of it, and the later will have the plug on the side-like Vince said, if the case plug has the diff pins and screw(diff than his pic) you will know its old right away

thanks for the help guys this is really helpful, just for knowledge on here ( talked to GM yesterday but they weren't supposed to answer conversion questions) is there any problem or foreseen issues I would have with doing a LS1 conversion with the older model?