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

Unless I was unreachable he would be kickin rocks this morning. Not for the break down, but for not saying anything about it.

 

Axle would be my first guess as well.

 

There is a chance that he didn't know if he had left the diff lock in when parked (trying to give the benefit of the doubt here).

 

Axle is probably not the case of the truck moves with diff lock engaged. If it were a rear axle the interaxle shaft would spin and the truck would not move. If it were a front shaft the rear would still move the truck with difflock disengaged. Being that you have to lock the diff to get it to move I am guessing the thru shaft is stripped or the parts that slide over the through shaft that the spider gears turn is broken and just spinning inside the power divider, that would still allow the front to spin when it is engaged and transfer power.

 

No telling how long it's been like that. Has h been with you long? I'd have a hard time keeping that hand on.

 

Explain that in a little more detail

 

Inside the power divider you have the input gear that has the sliding clutch and the spider gears And the gear that turns the front pinion and ring. The front driveshaft spins all of that, the spider gears in turn spin the teeth on part that slides over the thru shaft. If the teeth on the spider are bad, if the part that slides over the thru shaft is bad than the input will still spin the gear that turns the front rearend. My guess is something right there is broken and the gear and sliding clutch are fine so the front will engage. That's how a 404 works. Pull the power divider and I have a feeling that's where the broken parts are, usually we see the spider gears broken.

 

Clearly that is not how a power divider works. It is also called an "inter-axle differential lock". Essentially when it is not locked, it acts like an axle differential, allowing the wheel that doesn't have traction, to spin, and not putting an power to the one that has traction, except in this case it is the whole axle as opposed to just the wheel. When it is locked, then power goes to both axles, just like a locking rearend puts power to both wheels.

The weakest link in this chain would be either of the axles.