This problem started intermittently and now it's a permanent condition.

Basically it won't shift into 4 wheel drive and the light does not come on.

It's an automatic and the shifter feels as it always has, feeling like something is going on when I pull it back. 4H has never worked because the previous owner probably never used it and now it's seized (I assume) so the stick won't move into position.

I don't know what else I can say, let me know of any diagnostics I can do.

There are no abnormal sounds nor has their been in the past.

Thanks for any help you can offer. Winter has come and I can barely get out of the driveway lately.

 

Crawl under the truck, and hit the t-case linkages with some flavor of penetrant. (PB blaster works good for me, everyone has their flavor of the month though.) Get the shifter to move, then check for vacuum at the front axle. Should be vacuum at the outboard port in 2hi, at the inboard port in 4wd. (either range.)

 

He's got the later style shift pattern: 4lo, N, 2, 4hi from top to bottom. So yes you should fix your 4hi, but the vacuum problem is a common one. Way to go modern user friendly (read, lazy people) things.

 

For vacuum troubleshooting http://www.dodgeram.org/tech/repair/..._engagment.htm

 

I slid under the truck with a can of penetrating oil and didn't see any cables to spray it on, but I did see a disconnected vacuum line going to the transfer case. I cleaned it off and reconnected it. The 4WD now works!

I never would have guessed, I have no idea what the vacuum would do, does it actually push the gears into position?

 

The passenger side axleshaft is split into 2 pieces, CAD (Central Axle Disconnect) achieves the same goals as locking hubs, but fails more often when called upon to do it's job