spinning my wheels

all semi's pull on the last drive axle under normal conditions. it will either pull on the right or the left hub of the last axle. when the power divider is locked in it pulls on one hub in the front and one hub in the back. which ever are free. in the case of a spin out. like on ice,snow,mud it is a very bad idea to try and rock the truck back and forth trying to get it out. the reason is: it will at some point burn the bearings out in the power divider in the front axle. that is a $3k to a $4k part to have replaced. and drivers do loose their job over it. in the winter time. it is best to keep a bag of rock salt in the truck. in the mud or un even ground. it is best to get some one to pull you out. the power divider is mainly to help keep the truck moving in adverse weather conditions. it's not meant to be used as a 4X4 unit.

 

Power goes to the wheel that spins the easiest.

 

ALL SEMIS PULL ON THE LAST DRIVE AXLE?? Really.....might want to look into that a lil further---ya might say many do--might even get away w/most---But All?? Uh nope....

 

Cat litter is very good on ice.

And if you get in a jam pour some Clorox on your tires.

Many years ago driving on ice another hand & I was pulling into a truck stop, but when you turned off the street to enter the truck stop it was a shot steep grade. He would get about 1/4 the way up in & his tries would be just a spinning. he got out ran into the truck stop bough a jug of Clorox & poured a bit over each drive tire, them pulled into the truck stop without spinning a tire.

I would not advise the use of Clorox unless your in a jam, it can do damage to your tires. The driver i spoke of above I was around him & his truck ever now & again & the Clorox did not seem to bother his tires.

 

You are so far off here it's not even funny. The vast majority of US trucks are twin screw, 6x4 trucks.. what you're describing (and still inaccurately,at that) is a single screw, 6x2 setup of the sort common in Europe, but quite rare in the US (although Schneider did at one point run some Argosy cabovers with that setup, with a tag axle behind the live axle).
Power is supplied to both axles of a vehicle with a twin screw configuration at ato ll times, but, as torque will take the path of least resistance, the wheel that spins easiest will be the outlet for it... the power divider is essentially a differential, and, when you engage the PDL, it ensures that the outputs from the power divider to both axles continually rotate at the same speed, so that, if you do get a wheel slipping on one axle, you don't lose power to the other axle. In normal operation on a dry road, you would not want this locked, as, when unlocked, the power divider will adjust the speed of each output compensate for differences in tire wear.. say, for example, you have tires at 25/32nds on the #3 axle, and 14/32nds on the #2 axle.
Likewise, on each axle, you have a differential, which, in normal operation, also supplies power to both axle shafts, plus it allows an axle shaft to spin faster if need be than the other (such as in, say, a curve or a turn). Now, you don't typically see these on highway tractors, but on brush trucks, you'll often have differential locks, which, like the PDL, ensure that both axle shaft constantly rotate at matching speed. This prevents wheel slip and spin, and is ideal for those environments, but would be very hard on the tires and drivetrain on a hardball road if someone left it locked while going down the road (which is why you really don't see them on highway trucks).
Although I suppose some credit is due, as the rest of your post was accurate enough.

 

You know, in all my years, I've heard conflicting reports. I always thought the front axle supplys the power, and PDL engages the rear axle. But I've never been completely sure of that. One thing you must NEVER do, is engage the PDL when your wheels are spinning(you are stuck)in desperation. Scrambled eggs will result and a very costly repair will follow.

 

http://www2.dana.com/pdf/AXDR-0126.pdf

 

I don't know about that. It puzzling to me why the rear axle is the drive axle but the front one isn't. I have been driving a few trucks with inter-axle diff locks and a few times I would have to lock the diffs in order to get into a dock.

The other day I watched one driver try to back up into a dock to unload his straight truck (six axles with one rear lift axle), the back lift axle pulled the back drive axle up off the ground because of the slope and he was stuck. He kept trying until I told him to lock the inter-axle diffs and when he did, he zoomed right into the dock area. I drove that truck today, I had the same issue with the lift axle lifting the rear drive up at a different drop and I did the same thing, locked the IAD and went right into the dock area.

 

They both are. But, have you ever been driving on an icy road, and one wheel hits a slick spot, spins, and the other side of the axle loses power, because the torque will flow to the path of least resistance? The power divider works the same way. It's basically just another differential which feeds to the differentials of both axles. In normal operation, both of your axles are live, and are driving the vehicle.