4WD Questions
I plan to purchase a new tow vehicle within the next two years. At the present time, I am towing a 3500 lb travel trailer with a 2006 Honda Pilot 4WD. The 4WD is Honda's name; actually, it is AWD wit...
Forum Discussion
Our Expedition EL has the 2H 4Auto 4H 4L positions on the selector. We use it a lot like you describe. 2H in summer, 4Auto if weather starts to get bad. 4H only off pavement if required.
The Ford Control Trac works like this
2H - Front hubs unlocked, all power sent to rear
4Auto - front hubs locked causing front driveshaft to turn. The computer monitors the rotational speeds of the front and rear driveshaft but power is still 100% to the rear. If the computer detects a difference between the driveshafts, the transfer case clutch engages and starts sending power to the front but retains the ability to slip so nobinding occurs. So considering how 4Auto operates, it is NOT AWD in the same sense a Subaru (had one, loved it) or Audi is AWD where power is sent to all wheels all the time. If you punch it you will feel a bit of slip and the a catch as the front wheels are engaged.
You CAN simply leave the selector in 4Auto if you want, many years of Explorers and some Expeditions did not even have a 2H option, only 4Auto, 4H, 4L. I had one (2004 Explorer V8) and it worked great, never had to think about it. The 2H option for the Expy was to slightly help it's dismal fuel economy.
With standard traction control and roll stability control, 4Auto may be all you ever need.
4H - Fully locks the clutch in the transfer case, locking the front and rear driveshafts together for a 50/50 torque split. Will bind up on dry pavement.
4L - Engages transfer case reduction ratio, along with locking the driveshafts. It also engages a different throttle map for the electronic throttle, making it easier to modulate (the pedal becomes less "touchy") for precise manuvering. 4L 1st gear crawl ratio is 41.06 (4.17 x 2.64 x 3.73). Not too shabby!
The GM system is functionally almost exactly the same, not sure about dodge.
We love our Expy and would not hesitate to recommend it.
Daniel
The Ford Control Trac works like this
2H - Front hubs unlocked, all power sent to rear
4Auto - front hubs locked causing front driveshaft to turn. The computer monitors the rotational speeds of the front and rear driveshaft but power is still 100% to the rear. If the computer detects a difference between the driveshafts, the transfer case clutch engages and starts sending power to the front but retains the ability to slip so nobinding occurs. So considering how 4Auto operates, it is NOT AWD in the same sense a Subaru (had one, loved it) or Audi is AWD where power is sent to all wheels all the time. If you punch it you will feel a bit of slip and the a catch as the front wheels are engaged.
You CAN simply leave the selector in 4Auto if you want, many years of Explorers and some Expeditions did not even have a 2H option, only 4Auto, 4H, 4L. I had one (2004 Explorer V8) and it worked great, never had to think about it. The 2H option for the Expy was to slightly help it's dismal fuel economy.
With standard traction control and roll stability control, 4Auto may be all you ever need.
4H - Fully locks the clutch in the transfer case, locking the front and rear driveshafts together for a 50/50 torque split. Will bind up on dry pavement.
4L - Engages transfer case reduction ratio, along with locking the driveshafts. It also engages a different throttle map for the electronic throttle, making it easier to modulate (the pedal becomes less "touchy") for precise manuvering. 4L 1st gear crawl ratio is 41.06 (4.17 x 2.64 x 3.73). Not too shabby!
The GM system is functionally almost exactly the same, not sure about dodge.
We love our Expy and would not hesitate to recommend it.
Daniel
