Lift the truck at least 30 cm from the ground, following safety precautions. Drain transmission oil. Remove old transmission. Install new one. Refill transmission oil. Release jack.
first you pull the drive shaft out take the cross member down unhook the shift linkage take the starter out and converter bolts then bell housing bolts then reverse
This is a very large task that would require the entire exhaust system to come off along with several bolts that are in hard to reach areas. Most people would rely on professionals for this job.