Active 4x4
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in my experience when its on auto its like a beefed up traction control... if you want the awd feature just hit 4wd lock and it will be in full time awd.. if you hit the other modes all it does is change up the gear ratios..
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29 Posts
The reason I ask is because it rained good all day and noticed the gas mileage was worse the usual. Made me wonder if 4x4 was engaging, thus the worse gas mileage. Usually I get 27 city driving today was more like 24. I figure it shouldnt engage unless the wheels are slipping.
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Hmm are you talking about the light on the switch for the auto selector? Mine is on any time the Jeep is on.
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83 Posts
I noticed that as well. The mileage dropped in a rain storm, but I figured is was due to moving the water out of the tire's way, and the wind (it was very windy). My Auto light stayed on and I did not feel any change in the driving characteristics. I thought I would feel something if the back end started to push along with the front end pulling.
If the computer detected a need for 4X4, I also would have though it would select a new light to illuminate, like snow, sand or rock. Then go back to Auto when it didn't need it any more. But I don't know for sure.
If the computer detected a need for 4X4, I also would have though it would select a new light to illuminate, like snow, sand or rock. Then go back to Auto when it didn't need it any more. But I don't know for sure.
I too noticed reduced mileage when it's raining. I don't notice this drop in mileage with my rear wheel drive car in the rain. I'd bet the 4x4 system is activating. But I don't know if there is a way to tell when the rear drive wheels start to provide traction.
The gear ratios never change, they are fixed. What changes is shift strategy and traction control settings.
In auto mode, the system is on demand, meaning the rear axle is only engaged when a speed differential is detected between the front and rear wheels. Wet streets won't engage the system. The front wheels have to slip first. There is no light, as one isn't needed. The "Auto" mode light is all that is needed.
Engagement is hard to detect as the traction control kicks in also. Even with the TC off, engagement is really fast and almost undetectable.
If you are driving down a wet street and not sliding and slipping, you are in 2wd.
Engagement is hard to detect as the traction control kicks in also. Even with the TC off, engagement is really fast and almost undetectable.
If you are driving down a wet street and not sliding and slipping, you are in 2wd.
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3,643 Posts
A fraction of a second after front wheel traction goes below some threshold relative to the rear wheels, it activates.
A good example are my local toll booths. The booth has a metal plate covering a trench for power lines, etc. In most cars, it is under the front wheels when stopped to pay. When it rains, FWD cars get wicked wheel spin. My full time AWD car wouldn't even notice them. The renegade gets a blip of wheel spin and the rear wheels engage. Like not even a full rotation.
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114 Posts
What you're likely seeing is a drop in fuel economy due to increased road friction. Think about it, on a perfect road on a dry day, your rolling resistance is minimal. When it rains, your tires have to push water out of the way just to roll. The faster you go, the more the hydraulic resistance is trying to slow you down.
In a way, tires act like a pump. They're meant to move water out of the way so your tires contact the road properly. That pumping action uses up available horsepower and therefore fuel.
In a way, tires act like a pump. They're meant to move water out of the way so your tires contact the road properly. That pumping action uses up available horsepower and therefore fuel.
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32 Posts
Since you guys are on 4x4 topic, how good is the system on this jeep? They say it's a fiat power train and if so that just don't seem to me like a rugged off road machine. Anyone with real experience off roaring the renegade? Thanks for the help.
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29 Posts
Check out the off roading section, seems to be doing fine. Dont think Ive read of anyone breaking the power train off roading as of yet.
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Looks like the concensus is that rain causes poor fuel mileage so I wont worry about it at all. However I still have another question, in the manual it says not to lock/engage the 4x4 over 75mph. Does that also mean that 4x4 should not be used over 75mph at all? I didnt see anywhere where its say not to drive over 75 it just says dont engage it at over 75mph. Can anyone tell me different?
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246 Posts
If you're going over 75mph, don't turn on "snow" or "sand" or etc... wait till you're going slower or stopped. You can certainly drive over 75mph, if you want.
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