In my last truck I had many transmission problems. The stock tranny lasted about 2 weeks once I got the 6.0 and blower running right. The built tranny gave out once I started spraying it hard(9psi + 100shot, 5000+pounds). Getting a 4L60E to survive with this much horse power and weight just seemed pointless after all of that.

I had heard that swapping in a 4L80E wasn't all that hard, but I couldn't find anyone that had actually done it. I decided to just go for it and work through the problem as they came up. HERE is a swap page that is by no means complete but gives some idea of what had to be done to get it in there.

I got as quick as an 11.92 in my last truck which was a little heavier than this one. When that built tranny gave out, I was probably closer to a mid 11sec quarter mile time. That transmission cost over $2000.

The 4L80E I have in my new truck has taken me into the 10's with nothing more than a $109 shift kit. The tranny came from the junk yard and had at least 50,000miles on it before I got it. This really shows the strength of the 4L80E. I expect to have to build it at some point, but hopefully only once. I have seen ratings for built units in the 1200 horsepower range.
tranny pics
torque converter pic I let YANK choose my converter for me. They suggested the ProYank3400E for what I had planed. The first converter they sent me stalled all the way to 4000rpm before the turbo, and without any nitrous. Not sure what happened there. I sent it back, and it is much tighter now. It easily brake stalls to over 2000rpm but seems to fully engage by 2800. This is just exactly what this turbo set up seems to need. I can brake stall and get about 2psi of boost before I launch. My 60' times are usually in the 1.85sec range with boost only and launching at ~2100rpm and 2psi. With the 409 I have planed, the stall speed should be real close to the 3400rpm rating.
I also ended up with a transfer case from a HD2500 truck. It was the easiest to use with the 4L80E. The information I have found on this case puts the rating at around 2000ft/lb's at the engine. Based on that information I don't expect to have any problems with the transfer case. Currently I am still running the stock front and rear differential. When they give me trouble, I will probably try and get HD2500 parts under there.