If you have some mechanical ability, you can build your own tranny. It isn't really that difficult. There are some builders that are good at it, as they have done it so many times, but there are no "secrets" to the Allison. It's the same "secrets" that apply to any automatic transmission. The Ally isn't as complicated as some people make it out to be either. I've built 2 and they are holding over 500hp daily. My friends love them. I'm not a "builder," I just built a couple for friends of mine. I used to build streetmod racing trannies when I lived in NC. My only regret is not getting the parts from Jesse at Husker (I wasn't a member of this forum at the time).
PATC (as mentioned in an earlier post) does have a great kit. Their convertor is a Precision convertor, but it is not the same company as the Precision we all know and love. It's a knockoff. I don't know of anyone that has it and has been running it for long enough to report the durability.
Jesse at Husker Diesel has a killer price on the SunCoast GMax kit for your truck, and it comes with a full Transgo kit. The only thing you would need to buy is a TC and fluid. You'll need some small parts that aren't included in the rebuild kit to beef your tranny, but not many. Those you can pick up from PATC, if Jess can't get them. Using the GMax kit from Jesse, and a true Precision single oversized disc convertor you should be good up to around 500hp for around $2500 if you do it yourself. Over 500hp you'll need a triple-disc and more $$$, but the GMax kit will still hold.
There are a couple of builders that frequent this site. I'm sure they'll chime in, but I don't know of any that are near Mississippi.
The hardest part of rebuilding your Ally is removing and reinstalling it in the truck. Without the transfer case attached, the Ally weighs around 350lbs. Leave the t-case bolted up for easier removal/installation. You'll need a tranny jack and a floor jack.
