Towing - Stay in RWD or change to 4WD?

Much of the information posted is only applicable to traditional 4WD systems. Ford's ControlTrac system allows the vehicle to operate in 2High or 4Auto on any roads. The transfer case DOES HAVE a computer controlled clutch (acts as a center differential) that allows for the necessary slippage in 4Auto. In 4Auto the front hubs and front driveshaft are engaged, and the torque split is around 10/90 front/rear. If the computer detects a difference in driveshaft speed it can engage the clutch sending more torque to the front as necessary. Anytime we get rain or I hook up the trailer I set to 4Auto. Our previous Explorer did not even have the 2High option, it was always in 4Auto. It is awesome for towing, I don't have to think about it. It is not quite as seamless and smooth as a true AWD like the Subaru I owned, but it is pretty good. Combined with AdvanceTrac and RSC it does a great job keeping the Expedition going where you want it to and tire side down. Wikipedia has a very good article about ControlTrac, its history, and how it works.

mobeewan wrote:
4WD high is usually limited to 40 to 45 max. Any faster can cause damage.

I haven't seen a 4WD truck where 4-HI has a limited speed. I have ran both my old '96 F250 and my new F350 at 65+ MPH in 4-HI many times. The F250 was a manual transfer case with manual hubs, and I believe the manual said to slow to 55 to engage 4-HI, but it didn't mention anything about limited speed once it's in gear. My new truck is all electronic and will engage 4-HI at pretty much any speed. The only thing I do to help it along is back out of the throttle until I get notification it's engaged. I don't even think you have to do that though.

mobeewan wrote:
I've only ever driven above 45 once while in 4wd and it was by accident. After leaving a campground where everything was wet and a little muddy I forgot to shift back to 2wd. Was doing 60 on black top for about 2 miles. I slowed back down enough to shift back into 2wd.

I've never needed to go faster than 35 off road or in snow towing or not towing. I always though 45 was the limit for 4wd because that is the fastest for shift on the fly for my truck. I'll have to look at my manual again.

Anyway as previously stated you shouldn't tow on pavement in 4wd so why would anyone tow in full time 4wd?

Not sure where you're getting your info from but here in central NY we drive/tow on the highway in snow w/ 4WD on pavement 5 months out of the year at highway speeds. I'm sure we have the same trucks as you do down there.;) BTW I don't know a single person who's truck won't shift in and out of 4WD at any speed?:?

I've only ever driven above 45 once while in 4wd and it was by accident. After leaving a campground where everything was wet and a little muddy I forgot to shift back to 2wd. Was doing 60 on black top for about 2 miles. I slowed back down enough to shift back into 2wd.

I've never needed to go faster than 35 off road or in snow towing or not towing. I always though 45 was the limit for 4wd because that is the fastest for shift on the fly for my truck. I'll have to look at my manual again.

Anyway as previously stated you shouldn't tow on pavement in 4wd so why would anyone tow in full time 4wd?

mobeewan wrote:
4WD high is usually limited to 40 to 45 max. Any faster can cause damage.

Never heard that before.

I've driven 65+ in all my 4wd trucks, dating back to the 1979 GMC Jimmy I had in 1988.

mobeewan wrote:
4WD high is usually limited to 40 to 45 max. Any faster can cause damage. Read your manual. It should tell you.

4WD low is going to rev up the engine a lot sooner.

My 4WD shift-on-the-fly is good to 45 or 55 mph but not speed limited once shifted.
Low range you will run to the rev limiter fairly quick.

mobeewan wrote:
4WD high is usually limited to 40 to 45 max. Any faster can cause damage. Read your manual. It should tell you.

4WD low is going to rev up the engine a lot sooner.

Your overall gearing is not changed by putting it in 4WD but the slick road conditions should be the limiting factor for speed.

Generally if your truck is not full time 4x4 leave it in 2wd unless you are on gravel or slippery surface.

More accurately read the owner's manual. If you don't have one you can often download one for free. Whatever the manufacturer recommends will be the thing to do.

profdant139 wrote:
Here is one more tip -- let's say you are towing on gravel/mud/snow, probably going pretty slowly, towing out of your campsite and back to the dry pavement. It is important to remember that when you get back to the pavement, you need to shift out of 4 wheel drive.

So because I sometimes do not remember, I tell DW, "Remind me to shift when we get back to the road."

That way, if neither she nor I remembers and I fail to shift and damage the transmission, I have someone else to blame. ;)

Best Tip of all!

Here is one more tip -- let's say you are towing on gravel/mud/snow, probably going pretty slowly, towing out of your campsite and back to the dry pavement. It is important to remember that when you get back to the pavement, you need to shift out of 4 wheel drive.

So because I sometimes do not remember, I tell DW, "Remind me to shift when we get back to the road."

That way, if neither she nor I remembers and I fail to shift and damage the transmission, I have someone else to blame. ;)