by "Textured Soy Protein" (texturedsoyprotein)
Published 12/04/2017 at 12:36
by "Textured Soy Protein" (texturedsoyprotein)
Published 12/04/2017 at 12:36
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STARS: 1
These are the transmission and transfer case shifters of the new JL Wrangler. Specifically, the Sahara trim. If you look closely at the transfer case shifter, you’ll notice something never before seen on a Wrangler, and yet only mentioned in passing in most press coverage of the JL.
Look at the markings. Go ahead, I’ll wait. They say:
2H
4H AUTO
4H PART TIME
N
4L
That’s right, the JL Wrangler Sahara has full-time 4wd. Jeep’s using the Selec-Trac marketing name which has been applied to an assortment of different transfer cases over the years. The most common one is the NV242 which came on the XJ Cherokee and the I6-equipped ZJ and WJ Grand Cherokees.
This is a very popular and well-regarded transfer case, but me personally I’m not the biggest fan of its full-time mode because it uses an open center differential, not an LSD. The only time the Selec-Trac brand name has come with a center LSD is on the AMC Eagle. The Liberty had an optional Selec-Trac II system which used an MP3022 transfer case, but this is an electronic on-demand system which engages the front wheels on the fly.
So far I haven’t seen what specific transfer case Jeep is using on the Wrangler Sahara, but the Selec-Trac brand name could very well mean it uses an open center differential. If this is the case, it will probably use traction control to brake individual wheels to send power around to where there’s more traction.
Full-time 4wd is more desirable for on-road, foul-weather driving. It’s not as useful for serious off-roading. But if we’re being realistic here, even though the Wrangler is probably the SUV that’s most often used for Real Off-Roading™, there’s still plenty of people who buy them to drive around town. Those folks would be best served in bad weather by a full-time system.
If, on the other hand, you want the proper off-road goodies like the locking front & rear differentials and disconnecting sway bars, you’re looking at the Rock-Track part-time 4wd system on the Rubicon.
"McMike" (mcmike)
12/04/2017 at 12:36, STARS: 3
Holy shit, they got the upshift (+) downshift (-) right on the automatic shifter.
Praise be to FCA
"TheTurbochargedSquirrel" (thatsquirrel)
12/04/2017 at 12:39, STARS: 0
What’s the difference between Auto and Part Time? They both sound like modes where the car shifts between 2WD and 4WD automatically as it sees fit. Which mode would you use if you actually want a traditional, always engaged, 4WD mode?
"Takuro Spirit" (takurospirit)
12/04/2017 at 12:41, STARS: 0
"deekster_caddy" (deekster_caddy)
12/04/2017 at 12:42, STARS: 0
I used to have a ‘78 Dodge Ramcharger that had no 2H - it was full time awd until you locked the center diff. I can’t remember the pattern on the lever but it was something like
4
4H
N
4L
with 4 being ‘AWD’ - I’m not sure it actually said 4 but it didn’t say 2H, and I’m sure it didn’t say AWD.
the center diff was open as were both front and rear diffs, so if you stomped on it going around a corner you would just spin the inside front wheel (resulting in all sorts of steering nightmares). I called it ‘any wheel drive’ ;)
"E90M3" (e90m3)
12/04/2017 at 12:43, STARS: 2
They may have gotten the positioning correct, but it’ll still break after 2 uses cause FCA.
"random001" (random001)
12/04/2017 at 12:44, STARS: 0
So it really just has
2WD
AWD
Actual 4WD
"HammerheadFistpunch" (hammerheadfistpunch)
12/04/2017 at 12:45, STARS: 0
I have a feeling its less likely full time and more likely auto engaging. Which, potatoes tomatoes, but its not likely to have a center diff at all, just replacing the shift fork with clutches that can engage the front axle as needed. Could be wrong though, I am interested to learn more about it.
"HammerheadFistpunch" (hammerheadfistpunch)
12/04/2017 at 12:47, STARS: 0
Thats the question, is this AUTO or is this FULL TIME. My bet is on auto as you describe.
"Textured Soy Protein" (texturedsoyprotein)
12/04/2017 at 12:49, STARS: 0
There’s no shifting between 2wd and 4wd. That would be an on-demand system, not a center differential.
In the old NV242, 4H auto uses the open differential to vary torque on the fly. It has a 48/52 torque split. The issue with it is an open differential sends power to the path of least resistance. So on the Jeeps with the NV242 in 4H auto, if say, the rear wheels slip, the open differential would send more power to the rear wheels. Not ideal.
Modern cars with awd systems that use open center differentials use the traction control system to brake individual wheels, which sends power around. Let’s say the 2 front wheels have grip, the right rear doesn’t. The open diff naturally wants to send power to the rear axle, and an open rear diff would send power to that right rear wheel. But the traction control sees that wheel spinning so it brakes it which then causes the diffs to send power to the wheels that still have grip.
Ideally you’d at least have a center LSD with open front & rear diffs, but some vehicles with open center diffs & traction control manage to do halfway decent.
"Textured Soy Protein" (texturedsoyprotein)
12/04/2017 at 12:50, STARS: 0
Yes, full-time 4wd is another way to say awd.
“Actual 4wd” would require 3 locked differentials.
"random001" (random001)
12/04/2017 at 13:03, STARS: 0
So it doesn’t have locking diffs in 4L? Unless it’s the rubicon?
"Textured Soy Protein" (texturedsoyprotein)
12/04/2017 at 13:04, STARS: 0
I found this in the owner’s manual (p. 317 of the PDF):
4H AUTO
Four-Wheel Drive Auto High Range — This range sends power to the front wheels. The four-wheel drive system will be automatically engaged when the vehicle senses a loss of traction. Additional traction for varying road conditions.
That description sounds more like maybe some kind of auto-engaging on-demand system, but it doesn’t 100% rule out an open diff + traction control setup.
"Textured Soy Protein" (texturedsoyprotein)
12/04/2017 at 13:05, STARS: 0
4H PT and 4L both lock the transfer case. The front and rear lockers come on the Rubicon. The rear locker may be available on its own as an option, I haven’t deep dived into the available configurations.
"HammerheadFistpunch" (hammerheadfistpunch)
12/04/2017 at 13:08, STARS: 0
Yeah, thats what I would suspect. Something like the borg warner TOD thats going in the new raptor. Goes to show that there are certainly people like you out there who’ve made their opinions known about the benefits of an automatic 4wd system known though.
"Textured Soy Protein" (texturedsoyprotein)
12/04/2017 at 13:16, STARS: 0
I mean, if I’m being honest with myself, the systems in the Renegade, Compass & Cherokee are more than sufficient for on-road snowy driving. Even the non-Trailhawk trims have a snow mode for traction control and ability to lock the front & rear axles, to a point.
"HammerheadFistpunch" (hammerheadfistpunch)
12/04/2017 at 13:22, STARS: 0
If I had my druthers i would take a passive full time system over a lot of the “on demand” types these days, including supposed full time AWD systems that disengage the rear axle for fuel savings. Sure they eat gas and tires but I find they are so much more confidence inspiring in the snow. I am REALLY excited to see what a Torsen center diff full time system with good tires does this winter, I am expecting damn near unstoppable.
"FTTOHG Has Moved to https://opposite-lock.com" (alphaass)
12/04/2017 at 13:31, STARS: 0
That MT shift knob is sexy. I’m finding myself more and more considering buying an Unlimited to daily. Yes it’s a stupid idea but it’s the only four door convertible and I live somewhere where you can drive a Wrangler with the roof off 9+ months out of the year (and people do). My kids love them. The resale is awesome. Oh god what am I thinking.
"Textured Soy Protein" (texturedsoyprotein)
12/04/2017 at 13:41, STARS: 0
I agree, generally I prefer a setup that has some kind of base torque split and varies it on the fly. In the couple winters I had it, I never really got to try anything in my WK with Quadra-Drive II (3 Eaton eGerodisc eLSDs) that came close to challenging it. Both of those winters were below-average for snow here.
Apparently the snow mode in the Renegade, Compass & Cherokee keeps the rear axle engaged all the time, plus starts in 2nd gear. That plus being able to lock in tough situations is fine for 90% of on-road snowy driving. Only thing is if you’re cruising on the highway it doesn’t shift higher than 6th or occasionally 7th gear on the 9AT so you have to go back into Auto mode to cruise in the higher gears.
"DipodomysDeserti" (dipodomysdeserti)
12/04/2017 at 15:21, STARS: 0
!!! UNKNOWN CONTENT TYPE !!!
"Party-vi" (party-vi)
12/05/2017 at 09:49, STARS: 1
full-time 4WD
“2H”
"Textured Soy Protein" (texturedsoyprotein)
12/05/2017 at 10:48, STARS: 0
2H isn’t the part that’s new though, that’s been there since FOREVER, because that’s how long Wranglers have existed.
"Party-vi" (party-vi)
12/05/2017 at 11:20, STARS: 0
2H on a full-time 4WD system would be pretty new :P
"Textured Soy Protein" (texturedsoyprotein)
12/05/2017 at 11:30, STARS: 0
So I suppose you’re being pedantic about semantics that a full-time 4wd system isn’t full-time if it has a 2wd mode, but “full-time 4wd” refers to a mode that can be driven in 4wd all the time. Sure, awd mode would be a more accurate name, but hey I’m not the one labeling it.
There are plenty of other vehicles with 2wd and awd (“full-time 4wd”) modes. For example the XJ Cherokee and I6 ZJ and WJ Grand Cherokee, among many others.
"Party-vi" (party-vi)
12/05/2017 at 12:20, STARS: 0
I think it’s silly to call something full-time 4WD when you can dick around in 2WD.
"itranthelasttimeiparkedit" (itranthelasttimeiparkedit)
12/05/2017 at 22:35, STARS: 0
