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4WD CliffNotes

noreserve

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2019 JLUR, 1999 TJ Sport
I put this together in order to have a distilled reference for the 4WD-related operation and controls. The owners manual, like most every other reference, has far too much fluff and disclaimer info. I wanted something that I could put in my iPhone Notes app and refer to every so often. I hope it helps.

4WD CliffNotes


AutoStick
  • Can start in 1st or 2nd (3rd if in 4L). 2nd or 3rd useful for snowy or icy conditions
  • Holding selector in (-) will downshift to the lowest gear possible at the current speed
  • AutoStick disables when Hill Descent Control is active

2H (2 wheel drive)

  • Normal, hard surface selection that drives only the rear axle
  • When terrain becomes challenging/slippery, shift into 4H
  • Can shift into 4H with vehicle stopped or in motion - max preferred shift speed is 45 MPH (shifting effort will increase with speed and/or colder temps)
  • Do not accelerate or spin wheels when shifting transfer case (2H-to-4H) - maintain steady speed
  • Lifting off accelerator momentarily after shifting will engage/disengage transfer case more quickly

4H (4 wheel drive)
  • Normal off-road conditions - loose gravel/dirt, mud, slippery terrain.
  • Engages front axle in addition to the rear axle
  • Technically, no max speed, but realistically you wouldn’t be over 45 MPH
  • When terrain is no longer slippery or a change to hard surface roads occurs, shift back to 2H
  • When terrain becomes even more challenging, shift to 4L
  • To shift into 4L:
    1. Shift automatic transmission to (N) while rolling around 2-3 MPH
    2. While coasting around 2-3 MPH (no higher), shift transfer case firmly to 4L (do not pause transfer case in (N). You can be stopped, but this can grind transfer case gear teeth and require multiple tries - best avoided
    3. Once shift to 4L is completed, place automatic transmission in (D)

4L (4 wheel drive/lower gearing)
  • Extreme off-road conditions - steep inclines, challenging surfaces, rocks, obstacle navigation, etc. that will benefit from lower gearing and slower speed to “crawl” over terrain.
  • Maximizes torque to provide additional traction and maximum pulling power for loose, slippery surfaces
  • Compared to 2H/4H, it provides 400% (4:1) lower gearing on Rubicon (engine speed (RPM) is four times higher than 2H/4H at a given road speed)
  • 25 MPH max speed
  • When terrain becomes less challenging, shift back to 4H
  • To shift into 4H:
    1. Shift automatic transmission to (N) while rolling around 2-3 MPH
    2. While coasting around 2-3 MPH (no higher), shift transfer case firmly to 4H (do not pause transfer case in (N). You can be stopped, but this can grind transfer case gear teeth and require multiple tries - best avoided
    3. Once shift to 4H is completed, place automatic transmission in (D)

Locking Differentials (Front and Rear)
  • A differential (diff) can be locked to send equal power to both wheels on an axle
  • Can only be used in 4L and at 10 MPH or less
  • Used selectively in challenging terrain, as steering/turning is affected
  • The rear diff only can be locked or both rear and front diffs can be locked
  • Push down on switch (REAR ONLY) to lock only the rear diff
  • Indicator light by switch will flash until locked (or unlocked, depending upon selection)
  • Push up on switch (FRONT + REAR) to lock both front and rear diffs
  • If rear diff is locked and switch is pushed up, front diff will lock
  • If front and rear diffs are locked and switch is pushed up, front will unlock
  • The push button (OFF) will unlock both front and rear diffs
  • Diffs will unlock if transfer case is shifted out of 4L
  • Diffs will unlock if speed exceeds 30 MPH (will lock back once at <= 10 MPH again)

Sway bar disconnect
  • This allows greater front suspension travel (articulation) off-road to keep tires in contact with challenging terrain
  • Controlled with push button (SWAY BAR)
  • Not for use on hard surfaces
  • Can only be used in 4H or 4L at speeds up to 18 MPH - best to target <= 14 MPH
  • Will be automatically connected over 18 MPH
  • Will be automatically disconnected again once speed drops to 14 MPH
  • Indicator light on switch will flash until sway bar is disconnected, at which point it will light solid

Hill Descent Control (HDC)
  • Used only in 4L for low-speed hill descents (not for use uphill)
  • Enabled by pressing the HDC switch
  • Controls speed with braking
  • Vehicle must be below 5 MPH
  • Speed can be adjusted during operation with AutoStick (default in (D) or (1) is 0.6 MPH; goes up to 5 MPH in (8)). AutoStick 1-8 selections don’t shift gears - only speed is changed.
  • Use of gas or brake will deactivate HDC. It will remain enabled/ready, but not active during this time.
  • Light on HDC switch will flash if conditions are not met or if driver overrides
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noreserve

noreserve

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Great thread, When is it ideal to use lockers?
Thanks. Good question, but that would be a thread unto itself. One short answer is when traction is lost to a single tire that inhibits forward movement. A better answer is before that happens. Uneven terrain, especially inclines, where one tire will be in the air is the best example where locking will allow the other tire to hopefully maintain traction. This is typically done in the rear first and then in the front as needed. A challenging incline could warrant both rear and front lockers before starting out. The video from Ronny Dahl below is worth the 10 minutes.

 

Mamacast

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I put this together in order to have a distilled reference for the 4WD-related operation and controls. The owners manual, like most every other reference, has far too much fluff and disclaimer info. I wanted something that I could put in my iPhone Notes app and refer to every so often. I hope it helps.

4WD CliffNotes


AutoStick
  • Can start in 1st or 2nd (3rd if in 4L). 2nd or 3rd useful for snowy or icy conditions
  • Holding selector in (-) will downshift to the lowest gear possible at the current speed
  • AutoStick disables when Hill Descent Control is active

2H (2 wheel drive)

  • Normal, hard surface selection that drives only the rear axle
  • When terrain becomes challenging/slippery, shift into 4H
  • Can shift into 4H with vehicle stopped or in motion - max preferred shift speed is 45 MPH (shifting effort will increase with speed and/or colder temps)
  • Do not accelerate or spin wheels when shifting transfer case (2H-to-4H) - maintain steady speed
  • Lifting off accelerator momentarily after shifting will engage/disengage transfer case more quickly

4H (4 wheel drive)
  • Normal off-road conditions - loose gravel/dirt, mud, slippery terrain.
  • Engages front axle in addition to the rear axle
  • Technically, no max speed, but realistically you wouldn’t be over 45 MPH
  • When terrain is no longer slippery or a change to hard surface roads occurs, shift back to 2H
  • When terrain becomes even more challenging, shift to 4L
  • To shift into 4L:
    1. Shift automatic transmission to (N) while rolling around 2-3 MPH
    2. While coasting around 2-3 MPH (no higher), shift transfer case firmly to 4L (do not pause transfer case in (N). You can be stopped, but this can grind transfer case gear teeth and require multiple tries - best avoided
    3. Once shift to 4L is completed, place automatic transmission in (D)

4L (4 wheel drive/lower gearing)
  • Extreme off-road conditions - steep inclines, challenging surfaces, rocks, obstacle navigation, etc. that will benefit from lower gearing and slower speed to “crawl” over terrain.
  • Maximizes torque to provide additional traction and maximum pulling power for loose, slippery surfaces
  • Compared to 2H/4H, it provides 400% (4:1) lower gearing on Rubicon (engine speed (RPM) is four times higher than 2H/4H at a given road speed)
  • 25 MPH max speed
  • When terrain becomes less challenging, shift back to 4H
  • To shift into 4H:
    1. Shift automatic transmission to (N) while rolling around 2-3 MPH
    2. While coasting around 2-3 MPH (no higher), shift transfer case firmly to 4H (do not pause transfer case in (N). You can be stopped, but this can grind transfer case gear teeth and require multiple tries - best avoided
    3. Once shift to 4H is completed, place automatic transmission in (D)

Locking Differentials (Front and Rear)
  • A differential (diff) can be locked to send equal power to both wheels on an axle
  • Can only be used in 4L and at 10 MPH or less
  • Used selectively in challenging terrain, as steering/turning is affected
  • The rear diff only can be locked or both rear and front diffs can be locked
  • Push down on switch (REAR ONLY) to lock only the rear diff
  • Indicator light by switch will flash until locked (or unlocked, depending upon selection)
  • Push up on switch (FRONT + REAR) to lock both front and rear diffs
  • If rear diff is locked and switch is pushed up, front diff will lock
  • If front and rear diffs are locked and switch is pushed up, front will unlock
  • The push button (OFF) will unlock both front and rear diffs
  • Diffs will unlock if transfer case is shifted out of 4L
  • Diffs will unlock if speed exceeds 30 MPH (will lock back once at <= 10 MPH again)

Sway bar disconnect
  • This allows greater front suspension travel (articulation) off-road to keep tires in contact with challenging terrain
  • Controlled with push button (SWAY BAR)
  • Not for use on hard surfaces
  • Can only be used in 4H or 4L at speeds up to 18 MPH - best to target <= 14 MPH
  • Will be automatically connected over 18 MPH
  • Will be automatically disconnected again once speed drops to 14 MPH
  • Indicator light on switch will flash until sway bar is disconnected, at which point it will light solid

Hill Descent Control (HDC)
  • Used only in 4L for low-speed hill descents (not for use uphill)
  • Enabled by pressing the HDC switch
  • Controls speed with braking
  • Vehicle must be below 5 MPH
  • Speed can be adjusted during operation with AutoStick (default in (D) or (1) is 0.6 MPH; goes up to 5 MPH in (8)). AutoStick 1-8 selections don’t shift gears - only speed is changed.
  • Use of gas or brake will deactivate HDC. It will remain enabled/ready, but not active during this time.
  • Light on HDC switch will flash if conditions are not met or if driver overrides
This is great, wish someone would write this up for the Sahara, I don't even know when to disable the traction control :-( (newbie to Jeep Wranglers)
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