Towing - Stay in RWD or change to 4WD?

MikeJulieGDImagine wrote:
Out of curiosity, why is it bad to drive in 4WD on hard surfaces?

time2roll wrote:
no center differential at the transfer case causes the driveline to bind up with a lot of stress until one of the wheels slips.

Or until one of the gears breaks.

4WD is ONLY for slippery conditions because it requires slippage at one wheel or another from time to time. Use it on dry pavement and it not only endangers the mechanical bits, it also makes it dangerous for the driver, when one wheel simply slips from being forced by the mechanical pressure that has built up. If this happens at the wrong time in, say, going 'round a corner, it can cause a loss of control.

AWD has a center differential between the front and rear axles to accommodate these stresses without making tires slip or gears bind up. If your transfer case offers true AWD as well as 4WD, you can tow in AWD on dry pavement, and might find that it works better than 2WD. Or not.

I had a Jeep that offered both standard 4WD and AWD with selections such as you describe. It towed much better in AWD than in 2WD. Yours may not.

But whatever you do, do NOT attempt to drive, let alone tow, in 4WD on dry pavement. You will not like the results.

Some of the above comments assume that the 4WD system locks the wheels to the same rotation. But different 4WD systems from different mfrs have different ways of working. I can see from the Ford brochure for that year's Expy that its 4x4 auto mode would be fine to run on the highway. I can't tell offhand if 4wd high engages a differential lock or not. 4wd low definitely would not be appropriate, as it is not for highway speeds.

My Lexus GX470 has full time 4wd, and splits the power between axles all the time. That is its 4wd high. 4wd low gearing limits me to about 35 mph. Then there's a separate diff lock button for the tough spots. But like I said, every mfr does things a bit differently.

MikeJulieGDImagine wrote:
Out of curiosity, why is it bad to drive in 4WD on hard surfaces?

no center differential at the transfer case causes the driveline to bind up with a lot of stress until one of the wheels slips.

4WD Low is great for hitching up. Just don't forget to switch it back to 2WD.

MikeJulieGDImagine wrote:
Thanks Bill and Lanerd. I did read the owners manual and it did explain all of that about snow, mud, sand, etc. I just wasn't sure if having a trailer hooked up changed it. Thanks for clarifying for me.

Out of curiousity, why is it bad to drive in 4WD on hard surfaces?

When front hubs are in 4x4, the wheels need to turn at the same speed. When you turn, even just a little, one cannot go slower, and one faster, like normal. Instead they need to slide, slip, or jump, which it will not do on dry pavement. At some point, on dry pavement, the front end will lock up, or be damaged.

Jerry

Hard surface is not the problem. Hard dry surface is the no no.
Slick wet, icy or snow covered are OK to use 4WD.

MikeJulieGDImagine wrote:

Out of curiousity, why is it bad to drive in 4WD on hard surfaces?

Because tires may not be exactly the same diameter, and there will be different amounts of rotation when on a curve, between the steering axle and the fixed axle. Because of this, the tires and driveline components will be stressed resulting in more wear. Just engage 4WD in a parking lot and turn sharply for a demonstration of how bad it can get.

Thanks Bill and Lanerd. I did read the owners manual and it did explain all of that about snow, mud, sand, etc. I just wasn't sure if having a trailer hooked up changed it. Thanks for clarifying for me.

Out of curiousity, why is it bad to drive in 4WD on hard surfaces?

Just stay in 2wd unless you get off road and into sand, mud, snow or anything else where you might lose traction. Never run in 4wd on a hard surface....bad...bad... bad.

MikeJulieGDImagine wrote:
We just purchased our first camper this past Monday and we are making our maiden voyage tomorrow. Our tow vehicle is a 2013 Expedition EL and it has an option for 2WD, 4WD Auto, 4WD High, or 4WD low. Since I am new to towing what would be the best option to tow in?

Thanks

If the roads are dry, and clear use good ole regular 2WD. . . Only use 4WD if you feel the roads are not safe to continue without added traction.