So here goes. I just picked up a 99 yukon the tranny only has first and second. I have looked all over and searched and cant find this answer. What I want to know is what year 4l80e can be used in this vehicle. I see all sorts of swap write ups but no info on years. Any information or help on the above problem would be great. btw truck is OBS, 4wd 1500 5.7 4door. if any other info is needed please ask and help.