The front driveshaft has a rubber boot with a clamp on each end where the shaft inserts into the transfer case. Carefully cut or pry off the rear most clamp (closest one to the transfer case). There is a 99% chance you will destroy this clamp. Then procede to the front u-jount and remove the 4 bolts and 2 straps. Carefully push rearward or gently pry the u-joint loose from the flange. Have a roll of electrical tape handy to wrap around the u-joint cups so they dont fall off. Forgot to mention use chalk or crayon to make sure u-joint goes back in the same position. Then pull the shaft out of the transfer case output shaft. The boot will give some resistance. Upon reassambly if you destroyed the clamp will need a new one GM part# 26064275 about $10.00. I do know some techs that say heck with the clamp and apply grease inside the boot and just slide it back on without replacing the clamp.