Dads Dakota

My dad bought a 1992 dodge dakota with a 318 (4x4). He was recently plowing with it and 4wd stoped working 3 days later. I tried to figure it out and couldnt. I checked the wireing to see if it was unplugged I checked all the vacuum lines to see if they were cracked. I played around with the lever and sometimes it has 4wd in 2wd for a few short seconds. Im about to give up on it. :(


Also about 3 months ago his driveshaft flew out from underneeth the truck and broke off the shaft from the transfer case and cracked the O/D housing on the tranny.We replaced the O/D housing and the transfer case and now he has no O/D. Could someone give me some kind of explanation or somthing that will make this make sense....