transmission

I am getting ready to overhaul my transmission, it is a 4L60-e (I believe) it is in a 97 z-71 ext. cab 5.7. I have never done an overhaul b4 and WOULD REALLY APPRECIATE ANY HELP I CAN GET!! please!!!! ANYTHING!!!( I dont have $1600.00 for the shop)because my sun gear shell decided to die!!(no reverse, 2nd or 4th gear)-- I would like to know if there is any kind of upgrade I can do (since I will have it out of the truck) to extend the life, or just make it better than stock--i.e. shift kit?? I have been checking out many websites and kind of not sure--I do drive about 100-150 miles a day. if that helps in any way. Thank you for any suggestions.

I have rebuilt several th350's in the past, and though a diff, trans they are basicly the same. and in my experience the most inportant thing was details, keep everything clean and marked a digital camara might be helpfull doing this, there are a few specialty tools you'll need but other than that keeping track of everything is the hardest part, as for extra's, a shift kit is a good start, nothing monsterous, just a transgo or b&m kit, but the most inportant thing I have found over the years for a truck trans is a good cooler. you might consider an upgrade trans fluid as well, it is definately worth the little extra cost when considering cost of trans repair, and one of the major causes of trans failure is fluid breakdown due to heat, etc.