Power divider/axle interlock

[Racer X 69]

but, isn't there a speed limit you'd want to NOT go over..??? in other words, if the roads are slick, snow covered, etc, would you still stay at a reduced speed..?? say for instance, with the power divider/axle interlock off, your normal winter weather speed was say, 40 mph, would you still do the 40 mph..with the switch turned on..??

If the road surface conditions are such that I feel the need to lock the diffs, then I certainly won't be running the speed limit, especially in the places where I usually have to do so, like Wyoming where the speed limit is 75.

No, I am usually rolling along cautiously in the right lane at whatever feels comfortable while those dopes that run the FedWrex rigs blow my doors off at Warp Speed.

 

[Racer X 69]

i was hoping for a "general rule of thumb".

my truck does not have an "owners manual", as it is a lease truck, so i have nothing to refer to. i can check with my co-worker, maybe his truck has an owner's manual, but i would highly doubt that too. other than that, i have nothing else to go on.

Here's a thought. Get on the in internet, oh, wait, you already are.

Now open up another tab.

Type in Google.

Then type in the search box "owner's manual for {whatever rig you are driving}".

You should be able to find a downloadable pdf file of the owner's manual that you can peruse at your leisure.

 

[Racer X 69]

I don't have X-ray vision to see through my rears or differential, so I can't say for absolute certain.

I don't have x-ray vision, and I've seen your rea . . . . oh, wait, different thread.

Never mind!

 

[Tim]

Okay. I just talked to a mechanic about this because I DON'T know everything.

He said the PDL can be operated and locked in UP TO 35mph, which is the max speed the truck should be driven with it engaged and ONLY for short periods. Anything faster than that and it ACTS like it's working, but it's not. All it's doing is heating up from the gears rubbing together, but it's not working. Apparently, there was a driver here who locked it in going over Satus Pass and rolled on into the yard with it engaged the whole way, running 55mph. The differential was glowing red from the heat. Two hours later, the temperature of the oil was too hot to touch.

And whats the most common thing to do in the winter with tires? Either rotate them OR buy new ones and put them on the rear axle and put the used tires on the front axle, the absolute worst thing one can do, why? Just because of what you posted.

When you have new tires on the back and half wore out tires on the front you have now geared down the final ratio of the front front rear end, not a totally bad thing as long as you DONT engage the power divider. Once you engage it now has to try and spin the tires faster to keep up with the new tires on the back rear end. If your stuck in a mud hole not much if any damage will happen.
At road speed you got some spider gears in one hell of a bind trying to spin the smaller tires at a equal speed as the back tires, therefore things are going to get hot fast.

Just another reason to rotate your drive tires and wear them ALL out at the same time.

 

[Tim]

Here's a thought. Get on the in internet, oh, wait, you already are.

Now open up another tab.

Type in Google.

Then type in the search box "owner's manual for {whatever rig you are driving}".

You should be able to find a downloadable pdf file of the operator's manual that you can peruse at your leisure.

Fixed......
Owner's manual wont tell you nothing but where to get warranty work done at.

 

[Rigjockey]

Another thing to do would be to walk in to the office and ask where the truck manuals can be obtained? That would show that you care about the equipment and clearly you do by posing the question and the thread.

 

[Rigjockey]

Fixed......
Owner's manual wont tell you nothing but where to get warranty work done at.

Not only where to get warranty work at but, What scheduled warranty maintenance needs to be done. In my case a DPF filter that was put off and I ended up broke down and towed to the dealer, Even though before I left I stressed this was a PM issue, How much did that cost them? Plus a rental truck. Oh well not my truck, Even though I try to run it it like my own, Looking after the $$$$$$

 

[Injun]

Normally, I would replace both axle groups' tires at the same time. My deer strike plus some other maintenance stuff made that impossible this last go-round. I kept my four best tires worn to 8, 9, 10 and 10 and placed them on my rear axle. The new ones went on my front, main drive axle.

I do rotate my tires every second PM, have Centramatics and centering studs. I have all of my tires balanced when mounted, not just the outsides and have their balance checked every second rotation.

 

[Marc Letourneau]

Well I don't know much but I just go by what my old man has always told me... Only use it when you absolutely need it, And No that doesn't mean going down the road unless you are not going over 15 MPH. He has the owner operator mentality so when the **** hits the fan he is the one paying to fix it. In the Kenworths we have they have 3 different switches for the axles.. You can lock just the front, Just the rear or lock them all together.. If you can't get yourself out with everything locked up, Call the wrecker.. No sense destroying the truck.

I'm no mechanic but I would think that the new rear ends are much better than what they were years ago, And I would think that you may be able to get away with driving with them on a low speeds providing you need them. However I personally don't think it's necessary and I think if I said this to my father he would say "Not in my damn truck you ain't!". I guess it's all a matter of opinion on how you perceive the way it's worded in the owners manual.

 

[Rigjockey]

Normally, I would replace both axle groups' tires at the same time. My deer strike plus some other maintenance stuff made that impossible this last go-round. I kept my four best tires worn to 8, 9, 10 and 10 and placed them on my rear axle. The new ones went on my front, main drive axle.

I do rotate my tires every second PM, have Centramatics and centering studs. I have all of my tires balanced when mounted, not just the outsides and have their balance checked every second rotation.

I think you made the right choice financially and maintenance wise, sure,It would be nice to have all new tires but if some can be re positioned and are in good condition, Why throw out the money?

 

[colohayhauler]

Not too long ago, I had someone driving one of my trucks for a short period of time (an experienced truck driver or so I thought), and he left the PDL locked in and forgot about it. My usual driver got in and was complaining about it making a funny noise, discovered it was locked in, once he turned it off the noise quit. Nothing damaged yet, he probably drove 100 miles like that.

 

[Injun]

Before the deer strike and those maintenance items, I was in a position to replace all of them. The maintenance was stuff like a tensioner pulley, replace a belt that was starting to crack, stuff like that. I had to pony up $1K for my collision deductible, but Swift has been very good to me on this. They ended up mistakenly paying for some stuff that fell under maintenance because the work order numbers got mixed up. I called the claims guy as soon as I realized what happened. He looked it over and said, "You know what? Merry Christmas." ...to the tune of just over $1,100. I was ready to pay for my stuff, but I'm not going to turn down something like that. I simply asked, "Are you sure? I want to be square with Swift. You won't get in trouble...?" He just kind of laughed and said, "yes, I'm sure and no. Have a good holiday."

 

[Micabay]

Before the deer strike and those maintenance items, I was in a position to replace all of them. The maintenance was stuff like a tensioner pulley, replace a belt that was starting to crack, stuff like that. I had to pony up $1K for my collision deductible, but Swift has been very good to me on this. They ended up mistakenly paying for some stuff that fell under maintenance because the work order numbers got mixed up. I called the claims guy as soon as I realized what happened. He looked it over and said, "You know what? Merry Christmas." ...to the tune of just over $1,100. I was ready to pay for my stuff, but I'm not going to turn down something like that. I simply asked, "Are you sure? I want to be square with Swift. You won't get in trouble...?" He just kind of laughed and said, "yes, I'm sure and no. Have a good holiday."

Going for that Swift Recruiter of the Year nomination, eh?

 

[Les2]

Wow....lol! This was an interesting read.


I honestly don't know where to start. It's funny how I've read several different speeds you can run with the power divider locked in. Tim posted a pic of his switch and I didn't see anywhere a max speed you could lock it in. Now you'd think that would be very important, wouldn't ya?

Ok first off, the big difference between a front and back rear other than the obvious is the size of the ring gear. The back ring gear is much thicker.

Second is the simple fact that everyone has seemed to forget, the front rear turns just like the back one. Every gear in the housing is turning! When you engage it a gear slides into another gear which locks everything together. This is much easier to explain in person with a rear apart in front of me.

Third is te spider gears. You can put bald tires on one side and new on the other on the same axle and nothing will happen. This is what they are designed for. You can also do this axle to axle and nothing will happen.

Here's another neat fact.... Put all new drive tires on your truck and never rotate them. On my old sqhd's it would wear out the back right drive and front left. So if you think the front axle is doing nothing when disengaged, your wrong. It's still working, you just don't know it. So engaging it while cruising down the road in bad weather is kinda pointless cause its already working some.

Best advice is to call Rockwell and see what they say or even check their website. It may have the answers on it.

The mechanic injun talked to is full of ****! The only way that rear heated up that hot is if there was something else already wrong with it. Sorry injun and no offense.

 

[stonefly]

You could heat up a power divider by leaving it locked in. If it's unlocked then the difference in axle speeds is taken care of by the spiders in the power divider. If you lock the power divider, the spiders aren't working, and gears will be under stress due to the different speeds of the axles because of slightly different tire size. The locked power divider will cause tires to scuff and metal to become hot. Something has to give. When the diff lock is out-disengaged-the spiders take care of the difference in axle rotation speed.

 

[Injun]

None taken, [MENTION=9031]Les2[/MENTION].

I have the same mindset as [MENTION=5946]colohayhauler[/MENTION]'s dad. If it ain't needed, leave it alone.

When my PDL and Off Road switches are not engaged and I've done something stupid like park in my icy driveway with road-warm and salty tires then try to move two days later, it's my front axle that does all the spinning. It tries the passenger side first every time. When I lock my PDL, both sides of the front axle spin together like a posi-trac axle. When I engage the Off Road switch, both axles spin both sides at the same time. Then I get off my lazy ass and throw a chain on the ice in front of my passenger side front wheel group, kick it under the outside tire and haul myself out of the ruts my warm, salty tires melted into the ice.

I don't know what those switches will or won't do at higher speeds because I figure if I'm moving, I don't need to engage them.


[MENTION=9012]Micabay[/MENTION]....----------........where's [MENTION=10063]Tazz[/MENTION]'s birdie smiley? :neener:

 

[That guy]

Les pretty much covered it. Most of the Internet experts have never had one apart. Some of us have removed a power divider from an axle housing a hand full of parts at a time........... (Boy that make a loud bang!) Lol!

For what it's worth my KW has no speed limit for the power divider but the cross locks automatically disengage when you shift into high range.

 

[Duck]

None taken, @Les2.

I have the same mindset as @colohayhauler's dad. If it ain't needed, leave it alone.

When my PDL and Off Road switches are not engaged and I've done something stupid like park in my icy driveway with road-warm and salty tires then try to move two days later, it's my front axle that does all the spinning. It tries the passenger side first every time. When I lock my PDL, both sides of the front axle spin together like a posi-trac axle. When I engage the Off Road switch, both axles spin both sides at the same time. Then I get off my lazy ass and throw a chain on the ice in front of my passenger side front wheel group, kick it under the outside tire and haul myself out of the ruts my warm, salty tires melted into the ice.

I don't know what those switches will or won't do at higher speeds because I figure if I'm moving, I don't need to engage them.


@Micabay....----------........where's @Tazz's birdie smiley? :neener:

So it seems your "off road switch" is a simple diff lock on the front axle, ...

I wish our trucks had that. We just have a simple power divider switch, and in extremely cold temps, they don't even engage unless the axle is already warm from the road. Thick oil or something, I don't know.



Ours have some kind of traction control, but it's just some stupid electronic crap that's supposed to prevent loss of control in snow.

It's on full-time, but we have a button labeled "TCS" to temporarily disable that system, for "off road" driving, but we have a flashing light on the dash the whole time it's disabled. What the system does, is when it detects a drive tire spinning, you hear a little "psssst" like an air compressor unloader valve, ... it's some kind of little air cylinder somewhere on the truck that cuts the throttle to stop the tire from spinning. When driving off road, if you disable that system, it allows you to "light 'em up" and spin the tires as much as you want, ... for... some reason, ... if that's what you wanta do. (I guess if you're in a bobtail and feel like doing donuts in the snow, .. .. or maybe if you're stuck in mud and want to spin them really fast to fling the mud out from the treads.... never seen anybody do that in a truck, but it works with my ATV with knobbies, .. )



I've been stuck many times at home. In fact it's the only place I've ever been stuck to the point where I needed assistance from another vehicle. Twice, my little Ford tractor did it, one time the neighbor's big-ass John Deere pulled it out, and another time I had to get "clever" with a come-along, using it to pull between the front corner of the trailer, and the rear edge of the tractor frame to forcibly un-couple the trailer to push the bobtail forward, out of the little holes the tires were in. Then I re-hooked at a 45 degree angle so the tires wouldn't be in the same spots.

Every time it's been stuck, one hub spins, then when you hit the PDL, two hubs spin. Sometimes it's both on one side, sometimes it's diagonal opposites, but never both on the same axle, ... unless the truck is moving.

 

[GAnthony]

in general, regardless of whether the equipment can handle it, it's a bad idea to have the power divider locked when you're just cruising along.. So pretty much, only use it when you're stuck or doing low-speed maneuvering in a place you think you're likely to get stuck, like an un-plowed parking lot, or when you need to get up a hill.

which is when I USE the power divider/axle interlock.

If the road surface conditions are such that I feel the need to lock the diffs, then I certainly won't be running the speed limit, especially in the places where I usually have to do so, like Wyoming where the speed limit is 75.

No, I am usually rolling along cautiously in the right lane at whatever feels comfortable while those dopes that run the FedWrex rigs blow my doors off at Warp Speed.

i too stay in the far right lane, (in severe weather) and let the super duper pooper truckers go by, then when they go into the ditch, i flip them off and keep on going...

Here's a thought. Get on the in internet, oh, wait, you already are.

Now open up another tab.

Type in Google.

Then type in the search box "owner's manual for {whatever rig you are driving}".

You should be able to find a downloadable pdf file of the owner's manual that you can peruse at your leisure.

that's too much work for an answer to my question, that i may never get to see those 2 drivers ever again. plus my short term memory, makes me forget.

Another thing to do would be to walk in to the office and ask where the truck manuals can be obtained? That would show that you care about the equipment and clearly you do by posing the question and the thread.

rig jockey.....please refer to my posting...number 7, as to why i even asked this question. had you read the entire thread, then you could have seen where i have no concern for myself other than that i had wished at that point and time that i could have gotten into the conversation with the other 2 drivers, with "some back up" information for them.

as for me personally, i have a Penske lease truck, i couldn't really care that the mechanics think i care enough about the equipment.

they seem to do a fine job all by themselves in NOT "caring enough", repairing my truck right the FIRST TIME...!!!!

today (Saturday Dec 29th) makes it the 2nd time THIS WEEK i had to drop it off for THE SAME repairs, and it makes it the 4th time in the past 2 WEEKS of dropping it off to them..!!!

seems to me, SOMEONE ELSE should do some "caring"......

as i stated just above, i pretty much only use the axle interlock in a parking lot, if the lot is covered in snow, ice and making it difficult to maneuver.

 

[Les2]

You could heat up a power divider by leaving it locked in. If it's unlocked then the difference in axle speeds is taken care of by the spiders in the power divider. If you lock the power divider, the spiders aren't working, and gears will be under stress due to the different speeds of the axles because of slightly different tire size. The locked power divider will cause tires to scuff and metal to become hot. Something has to give. When the diff lock is out-disengaged-the spiders take care of the difference in axle rotation speed.

You are thinking of a posi-lock setup for something like a single axle. On a twin screw the power divider just engages the front rear so it will work constantly. Turning is not a problem with it on. Now you can get full lockers for a twin screw, I think thats what ThatGuy had on his KW.