by "HammerheadFistpunch" (hammerheadfistpunch)
Published 12/13/2017 at 13:34
by "HammerheadFistpunch" (hammerheadfistpunch)
Published 12/13/2017 at 13:34
Tags: Jeep
; JL
STARS: 1
I know you were wondering about the transfer case and the full time 4wd system in the Joop JL. Our man David says its the MP3022 case from the liberty. Which means it will act like Select Trac II. Its electronically controlled clutches that do the work, no center diff.
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More info
The MP3022 transfer case provides the following benefits:
Active, on-demand four-wheel drive requires no driver input.
Instantly anticipates slip and preemptively redirects torque as needed.
Vehicle stability under all conditions because torque is constantly being transferred.
4WD Low operation mode provides an advantage over vehicles equipped with a single-speed all-wheel drive transfer case.
Electric shifting between 4WD Auto and 4WD Low provides smooth operation and improved NVH control compared to systems with mechanical linkage.
Enhanced traction and stability provided by the Traction Control and Electronic Stability Program (ESP) working in tandem with four-wheel-drive.
A robust design and sealing for reliability.
Maintenance-free.
A neutral mode permits flat towing.
OPERATING RANGES
Transfer case operating ranges are:
Operating positions: 2WD - 4WD Auto - N - 4WD Low.
2WD = 2 wheel drive.
4WD Auto = Electronically controlled wet clutch for torque biasing.
N = Transfer case neutral for 4-wheel flat recreational towing.
4WD Low = Low range (2.72:1) part time mode.
The 4WD Low range is for off road use only. It is not for use on hard surface roads unless the road surface is wet, slippery, or covered by ice and snow.
The low range reduction gear system is operative in 4WD Low range only. This range is for extra pulling power in off road situations. Low range reduction ratio is 2.72:1.
I think its similar to a Borg Warner TOD drive where the clutching is done progressively as needed, should be very smooth. It also appears they’ve added a 4hi locked mode which wasn’t available in the Liberty. Another interesting quirk is that it requires the US of CV axle stubs instead of U-joints. Interesting stuff.
"BJ" (benjamin-bignell)
12/13/2017 at 13:46, STARS: 0
This is wonderfully nerdy!
Why does the case require “CV axle stubs instead of U joints”? Why does it matter? I don’t even know the difference betweem the two!
"HammerheadFistpunch" (hammerheadfistpunch)
12/13/2017 at 13:52, STARS: 1
U-joints input and output speeds aren’t the same at an extreme angle (like steering) which creates a hop and vibration.
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This isn’t an issue for a part time system when you are on a loose surface but it would on a hard surface. CV’s get around that problem. I kind of assumed that the 4wd system would sense a steering angle and reduce torque to the front axle to eliminate this effect but I now realize that it wouldn’t matter, ANY torque would still give you a vibe and a hop.
CV joints (constant Velocity) don’t have that issue.
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"Textured Soy Protein" (texturedsoyprotein)
12/13/2017 at 13:58, STARS: 0
Name changed y0!
I actually also asked him this question and he answered me too. I found this video describing MP3022 operation in the Liberty.
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It’s my understanding that the MP3022 is a progressive on-demand style computer-controlled clutch pack, but it at least starts out at 42 front/58 rear split, not rwd slip-n-grip.
Not quite as trick as the Eaton eGerodisc in the NV245 in the WK/XK/WK2 which can go to full lock but pretty good. There’s a video at that link but I can’t get it to embed.
Also apparently the JL Sahara has an optional rear LSD of some kind.
"HammerheadFistpunch" (hammerheadfistpunch)
12/13/2017 at 14:00, STARS: 0
I don’t know if that means that there is a constant on torque bias, or if thats its default “on” mode. Would be interesting if it really was “on” all the time at that bias.
"jimz" (jimz)
12/13/2017 at 14:01, STARS: 1
also worth noting that that style of CV joint (Rzeppa joint) is normally used at the wheel hub because it can work through a large range of articulation angles. Important for front (steer) wheels.
the inner ones are typically “tripod” CV joints, which tolerate less articulation angle but let the half-shaft extend and retract to allow for suspension travel.
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"HammerheadFistpunch" (hammerheadfistpunch)
12/13/2017 at 14:02, STARS: 0
Yup, like a slip joint/CV combo. I find it interesting they went with an open knuckle CV with boot instead of a closed knuckle and birfield, but I guess it cuts down on parts and as a bonus makes it easy to convert down the road as needed.
"Textured Soy Protein" (texturedsoyprotein)
12/13/2017 at 14:07, STARS: 0
I think what they mean by this...
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...is it starts out at 42/58 and varies from there.
The video also talks about using traction control to brake a spinning wheel to send power across an axle, but it sounds like it’s not doing any braking to send power front/rear like Mercedes and some Toyota (and probably others) setups.
"benjrblant" (benjblant)
12/13/2017 at 14:11, STARS: 0
I’m about as much a Jeep fan as the next Toyota guy, but the ‘18 JL Wrangler looks awesome. It seems a noticeable improvement over the JK in most aspects while still maintaining its style and staying true to its history AND its customer’s wants: adaptability, easily modifiable, and aftermarket friendly.
Meanwhile:
urgh.
"HammerheadFistpunch" (hammerheadfistpunch)
12/13/2017 at 14:26, STARS: 0
none of these system uses brakes to send power between front and rear axles, its not really practical because you would need to brake the entire axle would would have bad effects. Jeep BLD is just marketing speak like Toyota ATRAC. its just an external LSD simulator.
"HammerheadFistpunch" (hammerheadfistpunch)
12/13/2017 at 14:27, STARS: 1
yeah, we know a redesigned 4runner and Land cruiser aren’t far off in the distance and...well...im a little worried about them. Then again, the Tacoma doesn’t look bad.
"benjrblant" (benjblant)
12/13/2017 at 14:31, STARS: 0
4runner and Land Cruiser have their own market, but clearly a solid-axled vehicle with f+r lockers can and does sell in the US. Clearly there’s a market for it. And Jeep’s been running away with it competition free since 1998. Consumers win with automakers’ competition. I wish there was something comparable in terms of off-roadability.
"HammerheadFistpunch" (hammerheadfistpunch)
12/13/2017 at 14:32, STARS: 1
You and I both know that’s not happening. They wont even bother to fix the rear axle on the popular 70 series where its sold, they aren’t even going consider the hassle of making something like that available here. Not to mention Toyota has no interesting in going to toe to toe price wise with the wrangler.
"Textured Soy Protein" (texturedsoyprotein)
12/13/2017 at 14:35, STARS: 0
Hmm I might be mis-understanding the 3 open diffs + traction control concept.
I’m thinking of stuff like MB 4Matic, and the 1g Sequoia (until it got a Torsen in ‘05) and Highlander that each had 3 open diffs + traction control.
Somehow I got it in my head that the traction control could encourage power to move across the open center diff but I suppose that’s not necessarily the case.
"benjrblant" (benjblant)
12/13/2017 at 14:36, STARS: 0
I know Toyota won’t ever do anything about it. Maybe the Bronco will? Maybe GM will wake up from their culturally unaware trance and revive a K-5? Wishful thinking, but I can’t believe the Wrangler is STILL the only option.
"benjrblant" (benjblant)
12/13/2017 at 14:37, STARS: 0
Can you be “Textured Soy Protein, (formerly Atlas M)“?
"Textured Soy Protein" (texturedsoyprotein)
12/13/2017 at 14:39, STARS: 1
I was “Atlas///M is changing his name to Textured Soy Protein” for a week!
"benjrblant" (benjblant)
12/13/2017 at 14:40, STARS: 0
FINE!
"SilentButNotReallyDeadly...killed by G/O Media" (silentbutnotreallydeadly)
12/13/2017 at 17:45, STARS: 1
Yeah the choices are tight everywhere in the developed world. The only alternatives I can think of are the Suzuki Jimny (dunno about the new one)
and the Mahindra Pick-up (though this has a torsion bar front end, ugh)
...and apart from the Toyota’s and the Wrangler, that’s about it. Even down here...
"adamftw" (adamftw)
12/14/2017 at 06:59, STARS: 1
Should be great for all the moms.
I miss the Selec-Trac (NP242) case in my first XJ. That was the tits. I wanted to build a NP242HD with 4:1 low and SYE using a bunch of mix and match parts... I’m pretty sure the HMMWV and G Wagen used a version of the 242.
"benjrblant" (benjblant)
12/20/2017 at 11:22, STARS: 0
Grabbing coffee with someone who’s done a review on the press fleet! Anything I should ask about the newest Jeep?