i have a 1999 gmc sierra, regular cab, short bed. and i swapped a 6.0 into it. you guys have convinced me to ditch my 4l60e and swap a 4l80e into it instead. im now wondering what year transmissions and transfercases will swap into it. i dont wanna get something that i cant use. and is the transfer case im looking for a NP243?? THANKS ALOT GUYS!!!!