First of all, I bought the Mile Marker Full-time to part-time 4wd conversion kit. I installed it in my '78 F150. If your truck has the "lock" switch in the cab that lights up when the t-case is in "lock" then I have a few tips for you:
Tools needed:
-7/16" wrench,1/2" wrench,9/16" socket and ratchet with extensions,3/4" wrench,and 7/8" wrench. Also,1-5/16" socket with a BIG ratchet, hammer, and a flat screwdriver.
-NP203 T-cases with the "lock" switch only have 7 bolts holding the tailhousing to the t-case! NP203 t-cases without the switch have 8.
-The speedometer bolt must be lossened with the 7/16" wrench. The 7/8" wrench is used to remove the switch sensor on the t-case. The 3/4" wrench is used to remove the bolt directly below the switch which holds a spring and small ball bearing. Watch for the ball! The 1/2" wrench is used to remove the rear driveshaft from the yoke. After that, take the 1-5/16 socket and remove the nut that holds the yoke in place. After that remove the 7 bolts from the tail housing with the 9/16" socket,ratchet, and about 6" of extension. Take the screwdriver and pry the tailhousing loose;or hit it with the hammer. After this cup your hand under the output shaft and catch the 15 needle bearings that fall out when the shaft is removed. Next, remove the planetary gear.
-'74-'78 trucks have a bolt together gear with four bolts that hold it together. Take these bolts out and remove the spider gears, curved washers, and all the needle bearings. Install the solid wedges and insert the shaft into the wedges then install the other half of the gear and bolt it together.
-The next part is fun. Remember the 15 needle bearings? They have to go back intothe planetary gear. The ONLY way to do it is to put gobs of grease on every bearing so they will stick to the inside of the race.
-After installing the bearings, take a big, flat washer from the kit and slide it onto the shaft protruding from the t-case. Then, take the flat roller bearing and grease it up and slide it on the shaft followed by another big, flat washer.
-Now the output shaft must be gently slid onto the t-case shaft without disturbing the needle bearings inside. After that, install the tailhousing, gear oil, speedo, etc.
-Install everything but the rear drive shaft! tie it up where it wont fall. Place the t-case in either high or low lock and see if it will move forward or backwards. Then put the t-case in high or low. If the vehicle doesn't move then everything is working properly. Now install the rear driveshaft.

 

That by far has to be best post ever written on this board: very informative! Were the milemarker instructions good? I lost you a little bit on the operations of the t-case after the conversion; maybe you could restate. Again, great job and thanks for posting your findings.

 

Thanks for the comment!

Sorry about the unclear transfer case explanation.

Here goes: After installing the kit, leave the rear driveshaft disconnected. Then place the t-case in either high or low "lock", crank the vehicle and try to drive forwards. If it moves, great. Now, place the t-case in either high or low, now try to drive forwards. If the vehicle doesn't move, the kit is working correctly. You see, when the t-case is in either high or low "lock" it is in 4wd;enabling the vehicle to move without the rear driveshaft. However, when the t-case is in either high or low, it is in 2wd; Which would be driven by the rear driveshaft. Henceforth not enabling the vehicle to move with the rear shaft disconnected. I hope this was more clear!?! By the way, Mile Marker's instructions were mediocre (as with most directions) That is why I posted all this info. The instructions were vague at times, pertaining to my particular NP203.

 

 

that is exactly what i was looking for. i just rebuilt my np 203 this week and i forgot how the rear output shaft and all the other crap that goes with the part time kit. i needed the part about the fat washers and roller bearings thanks a lot. i guess the search function realy does work.