4x4 4H Question
11-15-2018, 08:07 AM
#3
Senior Member
No, not for normal highway driving. 4H locks your front and rear axles together and will cause binding in the drivetrain (mainly transfer case).
As long as you aren't on a high traction surface (like a paved road), then you go as fast in 4H as you can in 2H. The not turning while in 4x4 is in reference to driving on a paved road in 4x4...this creates extra bind due to the front and rear axles traveling different distances but forced to turn at the same speed by the transfer case.
What are the speed limits with 4h? I've heard people say not to turn when in 4H, why?
11-15-2018, 08:11 AM
#4
4H can be used for normal driving speeds. Regarding turning... depends on whether you have locking differentials or not. If you have locking differentials (or even one locking differential) you want to avoid too much turning on dry/non-slippery roads. With a non-locked or open differential, when your vehicle turns the outside wheels need to rotate faster to match the inside wheel. (The outside wheel has to rotate more through the turn as it is covering more distance.) If the differential is locked, both wheels will rotate together regardless of the situation. On dry pavement, this results in the outside wheel being drug around the turn. On slippery pavement the outside wheel can spin as needed so it doesn't bind.
What he said.
What he said.
Last edited by JerseyDoug; 11-15-2018 at 08:13 AM. Reason: I type too slow!
11-15-2018, 09:42 AM
#6
Senior Member
4H can be used for normal driving speeds. Regarding turning... depends on whether you have locking differentials or not. If you have locking differentials (or even one locking differential) you want to avoid too much turning on dry/non-slippery roads. With a non-locked or open differential, when your vehicle turns the outside wheels need to rotate faster to match the inside wheel. (The outside wheel has to rotate more through the turn as it is covering more distance.) If the differential is locked, both wheels will rotate together regardless of the situation. On dry pavement, this results in the outside wheel being drug around the turn. On slippery pavement the outside wheel can spin as needed so it doesn't bind.
What he said.
What he said.
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JerseyDoug (11-15-2018)
11-15-2018, 10:02 AM
#7
This not completely correct. Yes, you can engage 4H at any speed and it operates the same as 2H. However, the use of an e-locker differential does not affect the drivetrain binding that occurs when the transfer case is engaged. Just as you noted in your example above--where the wheels on the inside vs the outside of a turn travel a different radius and therefore, a lesser/greater distance--the front axle also travels a larger radius (greater distance) in a turn than the rear axle, and this is what causes the drivetrain to bind. Just as the OM advises against using the e-locker on high traction surfaces, the same applies to the transfer case. Both systems should only be used in limited traction situations.
what about the traction control? ok on any surface right?
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12B302 (11-15-2018)
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11-15-2018, 10:15 AM
#8
This not completely correct. Yes, you can engage 4H at any speed and it operates the same as 2H. However, the use of an e-locker differential does not affect the drivetrain binding that occurs when the transfer case is engaged. Just as you noted in your example above--where the wheels on the inside vs the outside of a turn travel a different radius and therefore, a lesser/greater distance--the front axle also travels a larger radius (greater distance) in a turn than the rear axle, and this is what causes the drivetrain to bind. Just as the OM advises against using the e-locker on high traction surfaces, the same applies to the transfer case. Both systems should only be used in limited traction situations.
11-15-2018, 10:18 AM
#9
Senior Member
E-locker is part of several option packages--not sure which ones--that included an electronically selectable locking rear differential. It is part of the 4x4 function switch on the dash and is engaged by pulling the selector **** out. As stated in OM, it should only be used in limited traction situations and only at slow speeds. I believe it automatically disengages above a certain speed, about 35 MPH if I recall correctly.
Traction control is part of the whole stability control/ABS/rollover mitigation software that is part of your BCM module. It functions autonomously and is always on in the background when driving, unless you disable it by pressing and holding the TCS button on the dash (see OM for how this works). It is also disabled completely when in 4L. As with many of the stability control features, TCS will reactivate automatically when the vehicle reaches a certain speed.
Traction control is part of the whole stability control/ABS/rollover mitigation software that is part of your BCM module. It functions autonomously and is always on in the background when driving, unless you disable it by pressing and holding the TCS button on the dash (see OM for how this works). It is also disabled completely when in 4L. As with many of the stability control features, TCS will reactivate automatically when the vehicle reaches a certain speed.
Last edited by icantdrive55; 11-16-2018 at 09:06 AM.