i have a 1999 four wheel drive ranger and the transfercase wont always engage, i can turn the switch and it will engage and worf fine then the next time it wont work at all, any ideas as to what could be causing it

 

Since no one has responded,maybe a suggestion or two,
There is a motor that shifts the gears in the transfer case. They do get dirty and hang up , so check the connections at the shifting motor and make sure the power is getting there when selected and if they are clean and good, the motor may need to be opened up and checked or replaced.