I have a 1999 Chevy Sub 2wd, with the 5.7 engine. Trans stopped shiftin into third and OD about a month ago, so I bought some sea foam and it cleared up right away. Well, that lasted about a month til I started slipping into every gear and by this week was barely driveable. I picked up a used trans from a salvage yard that was told to me to be out of a 2000 silverado 2wd and was labeled to be a 4l60e per the receipt. I dropped it off at a local mechanic just to make the swap and here comes the problem, he tells me that this trans doesn't fit. Says its shorter, and doesn't have all the same spots for things to fit on it, he thinks it looks just like a 700r or something. This is my only car and I have a family of five, I don't have the money at all to buy another one, and the salvage yard is telling me that it is a 4L60e and from what I believe to know, this should fit? Is my mechanic wrong, I definately do trust him, but he is not a trans guy, or is it possible that the salvage yard sold me the wrong trans. I REALLY need help on this guys, what should I do?????? I'm quite handy and have rebuilt small engines before, should I just order a rebuild kit myself for 150 and resell this trans? Or is there a way to make this fit? PLEASE HELP!