99 kenworth w900 won't move unless power divider engaged.

Did the driver spin the wheels a lot without the power divider locked in and did you hear an noises that were out of the ordinary? Unlocked, does the driveshaft to the rear diff spin and not put power to the wheels or do you not have any movement past the front diff?

 

I can't imagine the front diff being completely blown that badly but it's the only thing that comes to my mind

 

You have blown out the rear end, probably the front.

 

Yup just like Tampa say rear end out did he engage the lock when it was spinning.

 

Or you snapped a axle shafts .

 

I suspect the back diff. Drop a little oil out each and that will tell you where the problem is

 

I am putting my money on a broke axle.

 

+1
Either that or something in the front drive axles is toasted. Does the truck have diff locks? If so, lock in the front drive axle only. If it moves, broken/damaged axle. If not, the differential itself is damaged. If you have no diff lock for the front axle, the only way to know for sure what's toast is to start pulling the axle shafts. If they're good, you'll have to pull the diff.

Edit: when the shaft from the transmission turns and the truck doesn't move, does the inter axle shaft turn or not? If it does, rear drive axle, if not, the problem is in the front drive axle.

 

That's what I was gonna say. Probably an axle. Easy fix.