Truckee, CA73 posts · joined Nov 2025Rig2019 Wrangler Unlimited Rubicon JL 3.6, 35s
i live in Truckee and commute over Donner Summit on I-80 three days a week in winter. every storm i watch people in brand new four wheel drive rigs either in the median or crawling at 15 with their flashers on, and it is usually one of two problems. they are in 2H because they never touched the knob, or they are in 4H on a road that is half bare and the drivetrain is binding up.
my JL Rubicon has a part time Rock-Trac case. no auto mode. on mixed pavement i am in 2H and on solid snow or ice i am in 4H, and switching back and forth is part of the drive. the Saharas with Selec-Trac get 4H Auto, which is the thing i am jealous of.
so the question for the rest of you: which cases actually have a real auto mode, and does anybody trust it?
Rutland, VT14 posts · joined Nov 2025Rig2022 Bronco Badlands 4-door 2.7, stock 33s
Badlands has the advanced 4x4 case with 4A, automatic on demand engagement. on Route 4 over to Killington with slush, ice patches and bare stretches, i leave it in 4A and it does its thing. you feel it bite on the icy bits. on solid snow covered back roads i put it in 4H because i want it locked in, not reacting.
the base Bronco and some of the other trims have the part time case without 4A, so check the window sticker before assuming.
Boise, ID88 posts · joined Nov 2025Rig2017 4Runner TRD Off-Road, 2 in lift, 285/70R17
4Runner owners, this is your reminder. SR5 and TRD Off-Road are part time 4WD. no center differential, so 4H on dry pavement binds the driveline, you hear it and feel it in tight turns and you will eventually hurt something. the Limited has full time 4WD with a Torsen center diff you can lock, and that one you can leave engaged all winter.
the GX460 and Land Cruiser are full time too. every winter i see a couple of part time 4Runners come in with a driveline clunk after somebody drove 4H on dry roads for a week because their brother said it was safer.
Coshocton, OH38 posts · joined Nov 2025Rig2020 Grand Cherokee Trailhawk 3.6, 31s
Grand Cherokee Trailhawk here. Quadra-Drive II is full time, with an electronic limited slip in the back, so i never touch anything on the highway. on the snow i switch the Selec-Terrain dial to snow and it changes the throttle and shift points, which helps more than the 4WD does.
the real answer is tires, though, and you all know it. my Trailhawk on the factory all terrains was sketchy on glare ice at 30 degrees. same rig on a real winter tire was a different animal. four wheel drive gets you going, it does nothing to help you stop.
Rapid City, SD102 posts · joined Nov 2025Rig2009 Wrangler Unlimited Rubicon, 2.5 in lift, 33s, Warn VR10
for anybody reading this thread before a trip over the Sierra: California posts chain control levels on I-80 and US-50. R1 means chains or snow tires, R2 means chains on everything except four wheel or all wheel drive with snow tires on all four, R3 is chains on everybody and usually means the road is about to close. M+S on the sidewall counts as a snow tire there, but read the current rules before you go, they are posted by Caltrans.
and carry chains that fit your tires even with 4WD. at R3 your transfer case does not get you a pass. the Jeep build pages at jeep.com list which trims got Selec-Trac and which got Rock-Trac by model year, if you are shopping used and want 4H Auto.
Truckee, CA73 posts · joined Nov 2025Rig2019 Wrangler Unlimited Rubicon JL 3.6, 35s
report from last night. four feet of new snow up top, R2 from Kingvale to Truckee, i went over at 9 pm in 4H the whole way since there was not a bare spot to be found. counted eleven cars off the road westbound, two of them were big shiny SUVs with highway tires.
i still want 4H Auto. on my morning drive the road was plowed and wet in Truckee and packed snow at the summit and i switched four times in 20 miles.
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