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2007 Kia Sportage EX Luxury
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8 Posts
Discussion Starter #1
I was driving my 2007 Sportage EX and it suddenly started to rain heavily. When I reached a safe spot, I pulled over and turned on my 4WD LOCK. I resumed driving and I turned off the 4WD LOCK after I parked and before I turned the engine off. I noticed the vehicle jerk ever so slightly upon turning the 4WD LOCK off.

My question is: Is it safe to operate the 4WD LOCK while the vehicle is in motion?
 

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1995 Procharged Mustang Cobra, 2021 Sportage EX w/EX tech package
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4,657 Posts
No, it's not safe, you need to have the car stopped. You have a auto 4WD system, when the front tires spin your transfer case sends power to the rear, automatically. The only reason you would ever need to hit the lock button is if your are in need of traction when you are off roading or stuck some where.
 

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2007 Kia Sportage EX Luxury
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8 Posts
Discussion Starter #3
No, it's not safe, you need to have the car stopped. You have a auto 4WD system, when the front tires spin your transfer case sends power to the rear, automatically. The only reason you would ever need to hit the lock button is if your are in need of traction when you are off roading or stuck some where.
Thank you for letting me know. I don't go off road. So, is it correct to say that I would not use 4WD LOCK in rain or snow?
 

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06 Sportage/2012 Navara V6 TD
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304 Posts
Well I thought that the sprotage 4WD system uses a EMC (Electric Magnetic Clutch), where the Transmission Control Module (TCM) distributes the required torque between front and rear wheels. The degree of drive to the rear wheels is governed by a number of inputs including the amount of torque commanded by the driver, individual wheel speed/spin, steering angle. In fact, there is always some drive being transmitted to the rear wheels. Pressing the button simply engagues the clutches, however, after approx 30km/h, the clutchs are ramped down, and the car goes back to being just as it was before the button was pressed. As you slow again though, the clutches will re-engage bring back on the 4WD.

The transfer case is always sending the power to the rear wheels. It is the clutch coupling system at the rear diff that controls the amount sent to the rear wheels.

I would use the 4WD lock button in slippery conditions (i.e. snow/ice,mud, dirt tracks, even heavy rain and smooth roads), but if you are over 30km/h, then the 4WD system is essentially off.

This system is not like a traditional 4WD system that required you to be stationary to engage, particularly if you were transferring from hi 4 to lo 4.

I have had my car on a 4 wheel dyno, and as soon as the fron wheels started to turn the drums, the rear ones did as well, so this to me indicates that there is always a level of torque to the rear wheels, else they would have not turned at all.

The clunk you felt is the disengaging of the clutch system. Wait to you do spin and feel it engage when you don't expect it.
 

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2009 Sportage LX V6 4WD, 2011 Mack GU813 405M
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Finally some actual info on this system.....and if your information is correct, then so was i.....exactly how I figured it worked

I used it a few times this past winter, mostly getting started, where I knew wheel spin would set it off, as driveline HATE shockload. when the rear axle catches on its own...you know.
 
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