I bought this 2002 truck and it will not shift into 4x4. The lever is frozen.

 

Get under the truck and check the linkage.

 

Well, it's pretty rusty under there. I see the linkage and a tube/plunger lookin thing. I will disconnect the linkage and see if the transfer case shifts. If it does then i guess its the plunger lookin thing then. I have been soaking the entire thing with WD_40 for a few days but no movment yet. I paid 900 bucks for this truck . it only needed a little bodywork. Everything else works ok except this shift lever being frozen.

 

If you disconnect the level, try a cheater on the lever at the transfer case. If that won't work, then it might be an internal issue in the differential/transfer case.