I saw that site too. The information there is different than what I have been given from the local transmission rebuilding shop. According to the info sheets I was given the 2WD trucks had the L45 & L48 transmissions in them from 81-83. The 4WD trucks had the L52 transmission from 81-83. I have sen the company an email to ask what a L50 is and from what year as it is not listed in any of the info sheets I have from them. I will repost here when I have a clarification. This is a question that I have been asked before, so I will get it answered as soon as possible.