How to tell if power divider is locked

Try this. try to turn the front driveshaft backwards and forward, if it's real tight and difficult to move, the power divider is locked.
If it's locked you can try rolling backwards and forward until it's released.

 

Snowwy.. no offense but sometimes you really need to stop giving advise. Half of what you say is true but misleading as can be to people looking for whole truths. Sorry

 

i speak from what i've seen.

trucks i've seen stuck. including my own. spin right front, and left rear. axles i've seen break, including one i did. was always the right front.



playing in the dirt 10 years. i saw a lot of stuck trucks. and a lot of rookies break axles.

only drove ONE truck that had both power and differential locks. the rest were power dividers only.

if all the trucks had diff locks. there wouldn't be as many stuck trucks. most would have a chance at getting out. but as such. they don't. so they just sit there, spinning and digging a bigger hole in the ground. getting more stuck.

i've seen trucks spin themselves into the ground. literally. at which point they had to dump their loads so the trac hoe can pull them out

 

If you watch any loaded truck drag racing, you can see the reason for one axle having a tendency to break over the others. The engine crankshaft, which applies the energy to the drive train from the engine, is at a right angle to the axle shafts, which are the means to apply the energy from the drive train to the surface.

In a "power divider" tandem or tridem axles system, each axle has equal power applied, when unlocked or locked, on equal traction surfaces. In the unlocked position, and unequal traction surfaces, the axle with the least traction available will be the release point for all the power applied to go to.

When in the locked position, and on unequal traction surfaces, the power will be applied equally to the axle(s) that have traction as those that have none or less.

99% of todays power dividers, are in the unlock position when no air pressure is applied to the input line. If you have a wrench and can remove the line from the axle, (after bleeding all air pressure from the truck system for safety) then you can turn the switch either way, after replenishing the air supply, and label it when air pressure is on or off.

In My Opinion.

 

The volvo i drove in CDL school had both. It was awesome since the yard was a bud pit. You obviously couldn't turn with the dif locks on though

 

This is due to roll and pitch rotation caused by engine torque. If the engine ran in the opposite direction, the opposite sides of what you've seen would spin. All power will go to the point of least resistance. On equal ground, engine torque forces the left front down and the right front up. This makes it easier for the right front to spin, this is a function of roll rotation. It is usually a front drive that spins 1st, this is a function of pitch rotation. The point of traction is lower than the center of gravity, the pinion gear is trying to climb the ring gear. This causes the front of the vehicle to pitch up and the rear down. The rear drive has more weight giving it more traction.

the 3 differentials are there to allow all drives to spin at different speeds while still transmitting power. They work very well providing that all tires have enough traction to push the truck. The downfall is that all it takes is 1 to lose traction to make the whole system useless. The power divider gives the option get power to both axles equally, which can sometimes get you moving. This was still lacking in poor traction situations like snow, mud and loose dirt/sand. Traction control helps further by monitoring wheel speed and applying brakes to wheels spinning to get power to ones not turning.

It's not dumb to assume that the wheel that spins the most is the drive tire, but it is wrong. It's much more complicated than that, simple conclusions in complex situations are usually wrong.

 

how come seems like every thread about power dividers or rear ends someone shows there ignorance claiming x position is the main drive position or that x position will get power before y position.

its all the path of least resistance power divider in locks front axle to rear power will follow path of least resistance on front axle and rear axle. if you have full lockers all 4 positions spin equal speed

 

Deezl and Grape explained it good. You're only seeing what it does sitting still snowy. It has an inter-axle differential that transfers power to the axles depending on the speed and surface. It can't do it job on snow or ice because of a possible spin out it won't function properly. That's when you then manually lock it in.

 

Gotta love traction control on a car in snow with both wheels spinning...You get the wheel spinning fast and start sliding out and it throws the brakes on. You get going a little more and it slams the brakes. the rental i was in didnt have a disable switch and since both wheels were spinning at different speeds it just got all confused.

 

The OP asked about how to tell if the pd is locked or not. I hope the OP dont mind us going a little off topic, but here is a link with a couple pretty decent diagrams of the power divider and how it works. The info in the linked page is somewhat dated, but for the most part accurate.
Link to team run smart.