PW in snow?

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jtcarlsen67

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Just got word that my PW is in paint status...great news. My question that I have searched for opinions on is this:
1. How does the PW handle snow on the road?
2. Please clarify for me something about the locker bypass. If I don't have the bypass setup then is the truck never really in 4WD while operating on the highway?

Thanks.
Tim
 

usaf2006

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I'm sure the PW will kick ass in the snow. my old 1995 1500 was a beast in the snow. It's all about tires in my opinion.

No idea about #2 :)
 

crazy jerry

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sounds like you should do a lot of reading. theres a lever that puts it in 4x4. a knob locks the axles but only in 4lo. not familiar with the bypass but im sure its just something that allows the lockers to work in 4hi as well but this is a bad idea on the highways. you may have the misfortune to find out first hand
 
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jtcarlsen67

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Thanks Jerry. I have done as much reading as I can find. I typically don't make big purchases/decisions without researching the crap out of it. I guess I was still unsure if I had the whole locker bypass thing confused, so let me just say what "I think" I know and someone can correct me outright.

So 4WD is that all 4 wheels have the ability to independently function based upon how the truck senses the traction of each wheel. As an example: If driver front is on ice but pass front on dry ground the power shifts to pass tire as it has ability to keep traction better and move vehicle.

The 4Lo locker locks all four wheels with equal power regardless of whether they can get equal traction, is that right? The bypass will trick computer into thinking it's in 4Lo and thereby keep all axles locked irregardless of speed. So I guess this is bad on dry surface, at speed, because steering would be incredibly difficult? And yes I'm sure damaging to vehicle.

Let me know if I am way off base here. Thanks.

Tim
 

DannyMK2

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Thanks Jerry. I have done as much reading as I can find. I typically don't make big purchases/decisions without researching the crap out of it. I guess I was still unsure if I had the whole locker bypass thing confused, so let me just say what "I think" I know and someone can correct me outright.

So 4WD is that all 4 wheels have the ability to independently function based upon how the truck senses the traction of each wheel. As an example: If driver front is on ice but pass front on dry ground the power shifts to pass tire as it has ability to keep traction better and move vehicle.

The 4Lo locker locks all four wheels with equal power regardless of whether they can get equal traction, is that right? The bypass will trick computer into thinking it's in 4Lo and thereby keep all axles locked irregardless of speed. So I guess this is bad on dry surface, at speed, because steering would be incredibly difficult? And yes I'm sure damaging to vehicle.

Let me know if I am way off base here. Thanks.

Tim

you are correct. however, you dont need to drive around with the lockers in the snow, unless your well off the beaten path.

as far as the bypass goes, i dont think anybody is currently making them so unless you already have one i guess its not worth worrying about.
 

Low_Sky

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My 2015 handles great on snow with the stock Duratracs. The Duratracs even do pretty well on ice as long as you drive like you have a brain.

Traction control and the LSD take care of most of my traction needs on snow. I use 4HI intermittently, only when it's needed (starting from a dead stop, some turns/intersections, passing, deep fresh snow on the road, very icy conditions). The truck will tell you when you need 4HI in snow.


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Low_Sky

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Knik River, Alaska


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Csanders1992

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Thanks Jerry. I have done as much reading as I can find. I typically don't make big purchases/decisions without researching the crap out of it. I guess I was still unsure if I had the whole locker bypass thing confused, so let me just say what "I think" I know and someone can correct me outright.

So 4WD is that all 4 wheels have the ability to independently function based upon how the truck senses the traction of each wheel. As an example: If driver front is on ice but pass front on dry ground the power shifts to pass tire as it has ability to keep traction better and move vehicle.

The 4Lo locker locks all four wheels with equal power regardless of whether they can get equal traction, is that right? The bypass will trick computer into thinking it's in 4Lo and thereby keep all axles locked irregardless of speed. So I guess this is bad on dry surface, at speed, because steering would be incredibly difficult? And yes I'm sure damaging to vehicle.

Let me know if I am way off base here. Thanks.

Tim



4hi and 4low just simply lock the front axle to the rear axle via the transfer case. What your describing as 4wd is what traction control does. Traction control applies breaks to the spinning tire to give traction to the other side. Which doesn't really work that well.
The real cure for that scenario are your lockers, which I believe acts as a limited slip when not engaged. Lockers distribute power equally across the axle regardless of which tire has traction. Limited slips split the power 70/30, 30 going to the tire with traction.


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Low_Sky

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Tim,

I'm gonna break it down Barney style so you can fully understand what you'd be buying, since you seem a little mixed up on some of the fine details.

You need understand these terms:
Transfer case - locks the front and rear drive shafts at the same output speed.
Differential - allows left and right axle shafts to rotate at different speeds. The average speed of the axle shafts must equal the input (driveshaft) speed divided by the axle gear ratio (4.10 on a current PW). If the truck is moving in a straight line, both axle shafts are turning the same RPM. If the truck maintains it speed and turns, the outside wheel speeds up and the inside wheel slows down, but their average RPM is the same as the straight-line RPM.
Helical limited slip differential - Google this one, there's a lot to read about. They have some quirks. The rear diff in a PW is an LSD, so you have that working for you in 2HI, 4HI and 4LO (when unlocked).
Locking differential - locks the left and right axle shafts, temporarily turning your differential into a "spool". PW has one front and rear, accessible in 4LO.
Tire scrub - when a tire breaks traction to relieve binding stress in the drivetrain
Traction control - refer to the manual
Electronic Stability Control - refer to the manual

If driving in a straight line only, you can use whatever combination of locked/unlocked you want without issue, as all tires can turn at the same speed without scrubbing.

In 2HI, the truck can turn without tire scrub. The rear diff allows the rear tires to turn differentially. The front diff allows the front tires to turn differentially. The unlocked transfer case allows the front and rear axles to turn differentially (the front axle travels a longer path in a turn than the rear axle). **Very sharp turns can cause some rear tire scrub from the LSD** And I'm disregarding the front axle's Center Axle Disconnect, which doesn't change the outcome that all 4 tires can turn without scrubbing.

In 4HI, the truck must scrub one tire to turn. Same applies in 4LO unlocked. This is because the transfer case does not allow differential speed between the driveshafts, even though the front axle must travel a longer path than the rear axle in the same time. The front axle average speed must equal the rear axle average speed, so the lowest-traction tire will scrub. You will feel and hear this scrubbing if you try to do this on high-traction surfaces like dry dirt or hard packed, dry snow.

In 4LO, rear locked, one rear tire and one front tire must scrub to turn. On the rear axle, the lowest-traction tire must scrub since the locker does not allow differential action. On the front axle, the lowest traction tire must scrub because the front driveshaft average speed must equal the rear driveshaft axle speed, even though the front axle travels a longer path in a turn. Trying to turn with the rear locked on a high traction surface results in a lot of bucking as the tires bind and scrub, bind and scrub.

In 4LO, all locked, three tires have to scrub to be able to turn. This is why fully locked trucks don't like to turn, if you're on a loose enough surface to even try it. The PW is torque-limited in 4LO with the wheels turned to keep you from breaking something trying to turn while fully locked. I don't remember the exact wheel position that this torque limit kicks in, but I think it's around half-lock.

So, driving on road, even in snowy and icy conditions, the most I ever use is 4HI. I prefer to stick to 2HI because it allows all four tires to go around a corner without breaking traction. If 4HI is needed to fight under- or oversteer or gain enough traction to start from a dead stop, use it knowing that it will force at least one tire to break traction in a turn. This is usually acceptable, but it's worth knowing that it happens.

I'm not going to bother going into the weeds on traction control, but use your new-found knowledge of what your axles/tires have to do while driving to inform your understanding of what you read about these features in the owners manual (you can download it for free from Mopar).
 
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jtcarlsen67

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Thanks brother for taking the time to type all that. It explains things in a way that makes things clearer for me especially for driving on paved roads covered in snow vs the off road snow covered trails.
 
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