Power divider/axle interlock

[Copperhead]

Well, I am siding with blackw900 on this discussion. I have 3 switches in my dash that control traction (not also counting the ATC slip switch the does things electronically to improve traction).... a power divider lock switch, a forward axle locker switch, and a rear axle locker switch. You are not going to get 'positive' traction out of either drive axles without lockers installed. The divider just will provide power to both drive axles, but neither one is in a positrac state. True, both hubs on an axle are provided power and will turn at varying rates, but full power is only provided to the hub that will turn more freely. Hence, sitting in a spot with ice on one side and spinning while the other side is dry. Without full lockers, you will still just have one hub per axle provided power. In my case, I can get all four hubs full power, equally, regardless of surface they are on.

While the inter axle power divider will, essentially, provide a locker effect between the two axles, there is nothing positive about either of those axles compared to before. Just now you will have one hub per axle getting full power for 2 hubs total out of 4. Still won't help much under certain conditions. That is why i also spec'd full lockers on each axle to get past that issue.

 

[stonefly]

Well, I am siding with blackw900 on this discussion. I have 3 switches in my dash that control traction (not also counting the ATC slip switch the does things electronically to improve traction).... a power divider lock switch, a forward axle locker switch, and a rear axle locker switch. You are not going to get 'positive' traction out of either drive axles without lockers installed. The divider just will provide power to both drive axles, but neither one is in a positrac state. True, both hubs on an axle are provided power and will turn at varying rates, but full power is only provided to the hub that will turn more freely. Hence, sitting in a spot with ice on one side and spinning while the other side is dry. Without full lockers, you will still just have one hub per axle provided power. In my case, I can get all four hubs full power, equally, regardless of surface they are on.

While the inter axle power divider will, essentially, provide a locker effect between the two axles, there is nothing positive about either of those axles compared to before. Just now you will have one hub per axle getting full power for 2 hubs total out of 4. Still won't help much under certain conditions. That is why i also spec'd full lockers on each axle to get past that issue.

I am amazed at how many "drivers" operate their equipment without taking the time to understand how it operates.

I'm siding with Gus.


It's not a tug of war. You can have millions of people swearing to something and every one of them can be completely wrong, in unison, or in harmony. When it comes to mechanical misunderstanding, there are few things more common than the idea of a drive wheel or drive axle.

Originally Posted by blackw900

...A power divider on the other hand, engages the second rear end so that BOTH rear ends are used to transmit power as opposed to im stead of just one as it is under normal operating situations.

That is wrong, plain wrong, and it's the same old worn out idea of one of the two tandem axles being a drive axle. It's a misunderstanding. You can side with it all you want, but it's still wrong. The gears in a truck are not designed that way and they don't work that way. How many people are there in the world today? Some say it's already hit 7 billion. It doesn't matter if we all say say it. It's still wrong. There are a lot of so-called mechanics practicing out there who have the same misconception about the chunk. Don't worry, though, if one of them gets their mitts on your rig, because their misunderstanding won't cost you anything, because they're just gonna change a bunch of parts anyway, until you run out of money, and your truck is still not going to run if you happen to fall into their clutches.

On your truck you have a lock for every differential, and that's good, and I wish I had 'em, and when you throw in all the lock switches, your entire drive train turns without any differentiation. Guess what. You could still sit there with all 4 hubs spinning, or have you already discovered that? It can happen, depending upon the circumstances. Four way lockers are the best for getting out of difficult traction-challenged situations, followed closely by three way, with two way trailing way behind, and last but not least, the tandem axles where the inter-axle differential lock doesn't work, like my old cabover Freightliner, which doesn't have jakes, either.

I'll repeat something here that everybody can side with and be right at the same time. Here it is:

Originally Posted by stonefly

The power divider is nothing more than a differential with a driver-controlled lock. Once you lock it, it is no longer a differential.

WELL?

 

[Copperhead]

I suppose it could happen, anything "could" happen, that I just sit with all drive wheels turning, but it hasn't yet. Have had a couple of times where they were all fighting for traction, but I was making progress. And that was bobtail getting up my elevated ice covered driveway on the farm. Before, I would have had to have the wife get on the ag tractor and pull me on up the drive. But I can sure go a lot of places where I could never go before with only an interaxle lock. And it sure makes a difference when doing a drop and hook thing in a deep potholed unimproved drop lot.

 

[stonefly]

I wish I had 'em.

 

[Copperhead]

I wish I had 'em.

Sure nuff, you don't see full lockers spec'd on a road truck very often. Most folks don't give it much thought when spec'ing out a truck at the dealer. It is only when they run into a situation where they need it, then they realize it would have been a good idea. Since I stay north all winter long, it was in the forefront of my mind when I was putting things together on the order.

 

[Mire]

I don't think I've ever seen them on a road truck. To be honest, I don't see them on vocational trucks that often, save for the ones which actually stay on-site for the duration of the job, and are almost certainly going to need them. I know the road builder I used to work for stopped having them put on their trucks because they ended up spending a good bit on tires thanks to drivers who'd think it was okay to leave them locked in or else would forget to unlock them once they got on the hardball.

 

[ProDriver77]

I wish I had 'em.

I'd be happy just for an Inter-Axle!

 

[Rigjockey]

Thats pretty inaccurate...You're thinking of a diff lock that essentially make a non posi rear end into a posi rear end.
A power divider on the other hand, engages the second rear end so that BOTH rear ends are used to transmit power as opposed to im stead of just one as it is under normal operating situations.

Got to side with you on that one.

 

[CamelTrucker]

I'm not sure how your trucks are setup but I'll have a go at this. My Truck has dual drive axles that operate in "All Wheel Drive." What this means is if I were to raise my trucks drive wheels off the pavement with a forklift and put it in gear, all 4 hubs will spin. Unfortunately, AWD sucks for extreme traction issues. If I were to set the back end on the ground and jack one side of one axle only, all the power will go to that one hub instead of all 4 hubs. The Axle Interlock locks the front and rear differentials together making both the front and rear spin at the same speed. But if I jack one tire on each axle, all the power will go to those tires in the air.

This is where differential locks shine. You lock the differential side to side for positive traction in combination with the axle interlock, you can jack 3 hubs in the air and that one wheel on the ground will power the truck forward.

 

[Duck]

The other day I was trying to slide my tandems on an empty trailer, while parked on a skating rink in Worthington, MN.

Both left side drive hubs were spinning with the PDL locked. That means there ain't no differential between the two axles, ... it's just a simple lock.

With the PDL unlocked, you have a one-wheel drive truck. Hit that switch and it's a 2 wheel drive truck.

 

[Mire]

The power divider doesn't lock your differentials. If you have differential locks on your truck, they'll be actuated separate from the power divider. On any truck I've driven with one, there was one switch to actuate the power divider, then one switch (per axle) to lock the differential on each axle.

 

[Duck]

The power divider doesn't lock your differentials. If you have differential locks on your truck, they'll be actuated separate from the power divider. On any truck I've driven with one, there was one switch to actuate the power divider, then one switch (per axle) to lock the differential on each axle.

They should have them all tied to the same switch, and the switch should have it's on/off positions labeled as:

• Normal driving when you're not stuck
• Super-Ultra-Turbo-Redneck-Four-Wheel-Drive

That way all the idiots with the fingerless gloves & the flip-flops on their feet can understand what it's supposed to do.

 

[Mire]

Yeah, but then you'll get these people who panic at the slightest bit of moisture on the road, and flip their power divider on when there's really no reason to, and continue running down a hardball road like that. Can you imagine how much more some of these companies would end up spending just in tires if the power divider and differential locks were tied into one switch? And that's before we even get into the damage it can cause to components.

 

[stonefly]

The other day I was trying to slide my tandems on an empty trailer, while parked on a skating rink in Worthington, MN.

Both left side drive hubs were spinning with the PDL locked. That means there ain't no differential between the two axles, ... it's just a simple lock.

With the PDL unlocked, you have a one-wheel drive truck. Hit that switch and it's a 2 wheel drive truck.

negatory

 

[stonefly]

The power divider doesn't lock your differentials. If you have differential locks on your truck, they'll be actuated separate from the power divider. On any truck I've driven with one, there was one switch to actuate the power divider, then one switch (per axle) to lock the differential on each axle.

The power divider is a differential, no less than the differentials in the forward and rear axles. On most trucks, it's the only one that comes with a lock. If you want diff locks for the axles, you gotta pay extra, but just think, you get thr33 switches instead of one.

 

[stonefly]

I was just thinking. What if we had an entire country of people who had little knowledge of common, down to Earth things?

For example, consider the power divider in a truck. What if even truck drivers, the people who actually use the power divider, maintained silly notions about its design and purpose?

My guess is that if we had an entire nation of people this uninformed about the things that are part of their everyday lives, they'd represent a mother lode to people who see the opportunity to take advantage and seize it.

Why, we might even end up with a country that loses its liberty and falls into debt.

Why argue with people who don't understand simple things and don't care? Just take advantage of them.


Right?


Oh yeah, y'all are gonna rise up.


Yeah right.


You sure you know up from down?


My guess is that when everybody "rises up", they'll end up in the ground.


Why? Because people just ain't as smart as we think we are.


I could just let this go. You know, like take my football and go home, but being this is a trucker forum, and I'm a trucker, I think I'll just keep poundin' on it and see what happens.

 

[Duck]

Yeah, but then you'll get these people who panic at the slightest bit of moisture on the road, and flip their power divider on when there's really no reason to, and continue running down a hardball road like that. Can you imagine how much more some of these companies would end up spending just in tires if the power divider and differential locks were tied into one switch? And that's before we even get into the damage it can cause to components.

They've already been trying to make trucks idiot-proof. They've got those Bendix systems that cut the throttle when it thinks you're about to roll over, they have ABS brakes for those who are too stupid to operate manual brakes, they've got jake brakes that won't work below 30 mph, etc.

They should just tie them all to the same switch and have it set up to make an annoying alarm and a flashing light go off when you exceed 30 mph with that switch on. Nobody needs interaxle or diff locks if the road is good enough you can exceed 30 mph anyway, .. unless they're trying to pull a grade with a tail-heavy load, on hard compacted snow or something. (in that case they can just ignore the buzzer). Then if the truck exceeds 45 mph, something should automatically disengage it.

The power divider is a differential, no less than the differentials in the forward and rear axles. On most trucks, it's the only one that comes with a lock. If you want diff locks for the axles, you gotta pay extra, but just think, you get thr33 switches instead of one.

Nah.

On some trucks, the front drive axle is the normal, full-time axle. On others, it's the rear. Jack that axle off the ground & the truck won't go nowhere unless you hit the inter-axle lock. Jack the passive axle off the ground with the interaxle lock unlocked, and it won't make a difference, the truck will move, and knock over the jack.

Every time I've ever been stuck on the ice at home with one of my company's trucks, and I mean EVERY time, (it happens at least once per winter) it's one of the rear drive tires spinning. If the inter-axle thing was normally an open diff when unlocked, sometimes it would be the fronts spinning, especially when one of them is on ice and both rears are in snow. But no, .. it's always the rears spinning until I hit the PDL switch.

I'm guessing that the reason nobody's agreeing on this is the fact trucks are not all set up the same way.

 

[stonefly]

Nah.

On some trucks, the front drive axle is the normal, full-time axle. On others, it's the rear. Jack that axle off the ground & the truck won't go nowhere unless you hit the inter-axle lock. Jack the passive axle off the ground with the interaxle lock unlocked, and it won't make a difference, the truck will move, and knock over the jack.

Every time I've ever been stuck on the ice at home with one of my company's trucks, and I mean EVERY time, (it happens at least once per winter) it's one of the rear drive tires spinning. If the inter-axle thing was normally an open diff when unlocked, sometimes it would be the fronts spinning, especially when one of them is on ice and both rears are in snow. But no, .. it's always the rears spinning until I hit the PDL switch.

I'm guessing that the reason nobody's agreeing on this is the fact trucks are not all set up the same way.

Where do you get this information? You make it up?

If you have have an inter-axle lock, it's a diff lock. If you're forming your ideas based upon observation, you need more observation.


Normal, full time axle? Passive axle? That's simply darling.

If you have the inter-axle differential unlocked, and you lift any one of the four hubs off the ground, the truck won't move.


The fact that nobody's agreeing on this reinforces my ever strengthening conviction that humans are definitely not the brightest bulb in the biological chandelier.

 

[Duck]

Where do you get this information? You make it up?

I've been stuck on ice before and have observed which tires are spinning, with or without the interaxle lock engaged. I've discussed this with multiple mechanics.

If you have have an inter-axle lock, it's a diff lock. If you're forming your ideas based upon observation, you need more observation.


Normal, full time axle? Passive axle? That's simply darling.

If you have the inter-axle differential unlocked, and you lift any one of the four hubs off the ground, the truck won't move.

Some trucks ARE set up the way you're saying. But the Volvo's I've driven, and this KW I'm in are set up the way I described.

Every one of my company's trucks I've driven, except for the Freightshaker I had when I first hired on in 2005, had/have individual temperature gauges for the two drive axle differentials. On every single one of them, after going down the road about 100 miles or so with a heavy load, there's always one axle that's warmer than the other, because the gears are transmitting torque while the other is just along for the ride. And it's always the same axle that spins on ice when the inter-axle switch is disengaged.

The fact that nobody's agreeing with me on this reinforces my ever strengthening conviction that I am definitely not the brightest bulb in the biological chandelier.

Fixed.

 

[Tim]

Where do you get this information? You make it up?

If you have have an inter-axle lock, it's a diff lock. If you're forming your ideas based upon observation, you need more observation.


Normal, full time axle? Passive axle? That's simply darling.

If you have the inter-axle differential unlocked, and you lift any one of the four hubs off the ground, the truck won't move.


The fact that nobody's agreeing on this reinforces my ever strengthening conviction that humans are definitely not the brightest bulb in the biological chandelier.

Try lifting the whole front rear end off the ground leaving the back rear end on the ground and stand in front of the truck while someone cranks it up in gear and let us know how that works out for you.