so i swapped a 6.0 into my 1999 gmc 1500 that had the 5.3 . its got the 4l60e in it now but its new hp pretty much blew 2nd gear out. so would it be a better idea to buy a built 4l60e? or get a 4l80e to swap into it?? and with the 4l80e swap can i run the transfer case thats on the 4l60? or what one do i need? and will i need anything else to do the swap??? the motor im running is about 450 hp. just wondering how to fix this the cheapest way i can but still be reliable.