4:1 Rock-Trac Part Time 4wd system?

[rubicon4wheeler]

You realize that none of that is true? Think about being stuck in 2wd where 1 tire has 0 traction or is hanging in the air. Pre-BLD/traction control what happened? The tire with 0 traction just spun and the other tire did nothing. Was 100% of the power going to the spinning tire? Nope, equal power was going to each rear tire but because there was no resistance there was almost no power being made. There's a reason a dyno is also known as a load cell. Without resistance power simply can't be made. In 2wd is always 100% of the power to the rear axle and 50/50 split. BLD works not by magically rerouting power to the tire with traction but by braking the free spinning wheel and increasing resistance thereby increasing power output... to both wheels equally. In 4wd without an active center dif is always 50% front and 50% rear. With lockers and 4wd you can have 1 tire with traction doing all of the work, but it's doing it with 25% of the power as the other 3 tires are are obviously powered as everything is locked. The hard part for me to wrap my head around in the 1 tire free spinning scenario was how is the engine only producing a few ftlbs of force that it trashed to spin a tire while revving to 6k rpms. The answer is resistance.

I was trying to simplify the explanation. You're saying exactly what I was trying to convey. Both wheels on an open diff axle are getting the same torque, but only 1 (the one that's spinning) has any power. The one on ice is absolutely worthless, and because the open diff can't redirect any torque to the wheel with traction, it can't put power to the ground to move the vehicle.

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[Gvsukids]

Good for you

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[Zachanadandy]

I was trying to simplify the explanation. You're saying exactly what I was trying to convey. Both wheels on an open diff axle are getting the same torque, but only 1 (the one that's spinning) has any power. The one on ice is absolutely worthless, and because the open diff can't redirect any torque to the wheel with traction, it can't put power to the ground to move the vehicle.

Hp is simply torque over time. The power output is still the same to each tire. The tires are all 4 getting the same amount of torque and hp in 4wd. Even if only 1 has traction the other 3 are outputing the same force/power. 1 can be doing 100% of the work moving the vehicle, but the power output is the same to all. Lockers don't even change that. What they do change is the resistance as the 1 tire with traction can provide the resistance to massively increase power output to all 4 wheels.

 

[rubicon4wheeler]

Hp is simply torque over time. The power output is still the same to each tire. The tires are all 4 getting the same amount of torque and hp in 4wd. Even if only 1 has traction the other 3 are outputing the same force/power. 1 can be doing 100% of the work moving the vehicle, but the power output is the same to all. Lockers don't even change that. What they do change is the resistance as the 1 tire with traction can provide the resistance to massively increase power output to all 4 wheels.

Why quibble? We're making the same point, but I was trying to simplify it so people would understand the difference.

With a fully locked 4WD with 1 tire on asphalt and the other 3 on ice, only that 1 wheel with a tire providing any traction is having any effectiveness in moving the vehicle forward. It is getting 100% of the effective power distribution to the ground, and the other 3 are doing 0% of the work.

 

[White Eagle]

Occasionally I feel like I am greatly overthinking various problems in my life.

Then I log onto the forum.

Nah - I think I'm alright.

I’m all good too

I was just ranting about using a term but no followup to that particular term.

 

[ShadowsPapa]

You realize that none of that is true? Think about being stuck in 2wd where 1 tire has 0 traction or is hanging in the air. Pre-BLD/traction control what happened? The tire with 0 traction just spun and the other tire did nothing. Was 100% of the power going to the spinning tire? Nope, equal power was going to each rear tire but because there was no resistance there was almost no power being made. There's a reason a dyno is also known as a load cell. Without resistance power simply can't be made. In 2wd is always 100% of the power to the rear axle and 50/50 split. BLD works not by magically rerouting power to the tire with traction but by braking the free spinning wheel and increasing resistance thereby increasing power output... to both wheels equally. In 4wd without an active center dif is always 50% front and 50% rear. With lockers and 4wd you can have 1 tire with traction doing all of the work, but it's doing it with 25% of the power as the other 3 tires are are obviously powered as everything is locked. The hard part for me to wrap my head around in the 1 tire free spinning scenario was how is the engine only producing a few ftlbs of force that it trashed to spin a tire while revving to 6k rpms. The answer is resistance.

I can attest to the BLD system working as well as the limited slip........... I had LSD in my prior JTs. You may recall my fear about going to a JT without it and plowing snow up hill. Oddly, or maybe not so oddly from your point of view, this JTMX with open diffs in 4wa performed perfectly and I never once felt like it was going to get stuck or stop going up the icy drive with what was probably hundreds if not thousands of pounds of snow being pushed up the hill, on snow pack and ice by this JT.

This is what separates true 4WD systems like our Jeeps' from the AWD or faux-4WD systems of most vehicles, whereby clutch packs, viscous couplers, and open differentials do not lock and cannot distribute a meaningful percentage of the engine's power to the tires with traction.

Totally disagree!
I also will say - even with clutch packs it's locked like any other differential. Your transmission works on clutch packs and people never question it being locked solidly, a motorcycle is clutch packs, heck, a stick works with a dry single disk clutch system via spring pressure............. so these transfer cases can be just as effective as any other once it has applied max pressure to the clutch packs. It's in true 4 wheel drive mode.
So you are saying that a manual transmission cannot possibly transmit full engine power because there's a single clutch disk applied by springs, and that an automatic can't transmit full engine power because it has clutch packs? These full time transfer cases can sure transmit full power - just like your transmission can. I've seen automatic transmissions ripped apart because the clutch packs apply so well - cases busted, shafts busted, and so on. The full time transfer case, when it's applied full torque, can indeed act like any other. Yes, the viscous coupling can transmit the full torque - I've quite a history with that sort of transfer case. I've seen things busted because that fluid acts like a solid with enough slippage, and things can be broken, they can be that strong.

 

[ShadowsPapa]

A vehicle with traction control or limited-slip diffs may be able to scramble up a difficult section of trail, but it will take wild wheelspin and higher-than-necessary speed to do so.

No, it doesn't take wild wheel spin. The ABS in these is so accurate it actually can limit or prevent trailer sway. It checks for fractions of an RPM difference. Plow snow with one of these - no wild wheel spin is needed. It works even before you get a full revolution of a wheel. Come ride with me in mine when I plow a heavy, wet snow with pack and ice under the truck next time and see just how fast these things work and how quickly things get applied.
And if you look at how a LSD works, at least those I've rebuilt and worked on, wild wheel spin isn't involved at all.
Over half of the cars I've owned have had limited slip - I don't define a partial rotation of a wheel as wild wheel spin.

 

[rubicon4wheeler]

Totally disagree!
I also will say - even with clutch packs it's locked like any other differential. Your transmission works on clutch packs and people never question it being locked solidly, a motorcycle is clutch packs, heck, a stick works with a dry single disk clutch system via spring pressure............. so these transfer cases can be just as effective as any other once it has applied max pressure to the clutch packs. It's in true 4 wheel drive mode.
So you are saying that a manual transmission cannot possibly transmit full engine power because there's a single clutch disk applied by springs, and that an automatic can't transmit full engine power because it has clutch packs? These full time transfer cases can sure transmit full power - just like your transmission can. I've seen automatic transmissions ripped apart because the clutch packs apply so well - cases busted, shafts busted, and so on. The full time transfer case, when it's applied full torque, can indeed act like any other. Yes, the viscous coupling can transmit the full torque - I've quite a history with that sort of transfer case. I've seen things busted because that fluid acts like a solid with enough slippage, and things can be broken, they can be that strong.

No. I'm talking about clutch based limited slip diffs. They're not very effective at limiting slip, and they wear out really fast when used off-road. Worm gear (Torsen type) LSDs are the ones that work decently and which last the life of the vehicle.

 

[rubicon4wheeler]

No, it doesn't take wild wheel spin. The ABS in these is so accurate it actually can limit or prevent trailer sway. It checks for fractions of an RPM difference. Plow snow with one of these - no wild wheel spin is needed. It works even before you get a full revolution of a wheel. Come ride with me in mine when I plow a heavy, wet snow with pack and ice under the truck next time and see just how fast these things work and how quickly things get applied.
And if you look at how a LSD works, at least those I've rebuilt and worked on, wild wheel spin isn't involved at all.
Over half of the cars I've owned have had limited slip - I don't define a partial rotation of a wheel as wild wheel spin.

The next time you watch a traction-control-only vehicle attempt the Rubicon Trail, report back to us on how much wheelspin you observe.

I'm not talking about a flat road with a little snow on it. That's easy for a traction control system to cope with because there's so little ground torque to deal with.

 

[ShadowsPapa]

No. I'm talking about clutch based limited slip diffs. They're not very effective at limiting slip, and they wear out really fast when used off-road. Worm gear (Torsen type) LSDs are the ones that work decently and which last the life of the vehicle.

Limited slip are more for road conditions, not off road. NO ARGUMENT on the Torsen type for off-road or harsh use situations. I'd likely have moved that direction if I still had a JT with the limited slip if the thing ever wore out.
I've never worn out limited slip in anything I've owned, sort of ironic in a way because here in Iowa, even our streets and highways are abusive most winters.

 

[ShadowsPapa]

The next time you watch a traction-control-only vehicle attempt the Rubicon Trail, report back to us on how much wheelspin you observe.

I'm not talking about a flat road with a little snow on it. That's easy for a traction control system to cope with because there's so little ground torque to deal with.

With a little snow - LOL.
I get your point on the rubicon trail comparison - but "a little snow" makes me laugh. We've seen some pretty capable vehicles get hung up bad in our "little snow" flying up over the hood as you drive.

 

[Zachanadandy]

The next time you watch a traction-control-only vehicle attempt the Rubicon Trail, report back to us on how much wheelspin you observe.

I'm not talking about a flat road with a little snow on it. That's easy for a traction control system to cope with because there's so little ground torque to deal with.

We ran the rubicon in the wife's JLUR and only turned on the lockers 1 time. Picking good lines, throttle control, and the BLD are plenty capable. Often I see people with lockers default to using them for every obstacle and then pretend they needed them.

 

[ShadowsPapa]

Limited slip also don't rely on wheel spin to work. In fact, the opposite. The axial forces created by the bevel gears working on the axle with traction actually lock it. So you don't get wheel spin with a properly working LSD - the torque transfer is instantaneous.
You don't get wheel spin with a working LSD - it locks due to the fact the bevel gears in the carrier push against each other, locking the clutch pack before the wheel spins.

I don't know where the idea that you get wheel spin first comes from - maybe the LSD was problematic or worn out due to improper fluids or additives.
On the side with no traction, there's no force against the clutch pack to cause heat or wear. It takes traction to engage the clutch pack, locking the carrier gear to the axle with traction.

 

[White Eagle]

I have a YJ with Eaton Detroit truetrac mechanical LSDs and I added another handbrake where I can apply individual pressure as needed to either back wheel to trick it into doing what I want (If needed). Each back wheel has its own brake handle.

I got duped into this Rubicon because the price was right but for what I do I prefer Detroit trutrac front and rear.

I don’t have the stupid sway bar on the YJ trying to reconnect at speed because I have no swaybar. I’ll probably remove the front swaybar on this rubicon all together.

I have 2,600 miles as of today on this Gladiator Rubicon and 2,300 of it has been off-road in 4x4.

I can’t afford any wheel slip or spinning going to my ranch because the flint rock will eat the tire.

 

[Gvsukids]

I don’t have the stupid sway bar on the YJ trying to reconnect at speed because I have no swaybar. I’ll probably remove the front swaybar on this rubicon all together.

Buy a the Tazer device and then you can disconnect the swaybar at any speed.

https://www.jlwranglerforums.com/fo...-reconnecting-above-18-mph.62428/post-1331918

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