Not an Escape question per se - 4WD v 2WD with locking axle

[hlrosenberger]

Can anyone explain the difference between 4WD v 2WD with locking axle? Is one better than the other for off road or snow?

[Bill and Earline]

Do you have any particular vehicles in mind for this discussion?

[dstreight]

That's a bit of a loaded question. Many modern OEM 4-wheel drive systems incorporate traction control instead of locking type differentials. Generally, they excel in almost every situation requiring effective traction.

Locking style differentials are great too but not so good if you are traversing a slippery off-camber slope; the "locker" will tend to pull you down in the direction of the off-camber. Whereas traction control will be more adept at keeping you pointed along the trail path.

There are too many possible scenarios and additional needed details to distill a real world answer to your general question.

[hlrosenberger]

Yes, F-150. or F-250. And the context of my question is - towing the Escape 5.0 off road.

[hlrosenberger]

What do you mean by a off-camber slope?

[Bill and Earline]

A "locking axle" would generally describe a locking differential, with a differential being the gear set that sends power to each axle/wheel. It's the large central part you can see in the back of most pickup trucks. Mechanical lockers (differentials) will physically engage or lock each side requiring each axle and wheel to turn. An open (non-locking) differential can have one rear wheel spinning on wet grass and the other rear wheel doing nothing.
Some modern differentials will lock when wheel spin is detected, thereby giving you a chance, since both rear wheels are trying.
Most people have some idea what 4 wheel drive is, but there are a great variety of systems, and with open differentials on front and rear, you could have both the front right tire and the back right tire spinning on ice, and still be stuck. In that case you have two wheels trying, but not all four. There are limited slip differentials that add some power to each wheel and there are various sensor systems that detect slip and try to send power to an idle wheel.

That's a start. See what other say.

[gbaglo]

My RAV4 has a button you push to lock all-four wheels. Never pressed it, but I assume power would be applied to all the wheels equally.
I still have 650 pages to go to get through the Highlander manual.

[Iowa Dave]

Originally Posted by Bill and Earline

A "locking axle" would generally describe a locking differential, with a differential being the gear set that sends power to each axle/wheel. It's the large central part you can see in the back of most pickup trucks. Mechanical lockers (differentials) will physically engage or lock each side requiring each axle and wheel to turn. An open (non-locking) differential can have one rear wheel spinning on wet grass and the other rear wheel doing nothing.
Some modern differentials will lock when wheel spin is detected, thereby giving you a chance, since both rear wheels are trying.
Most people have some idea what 4 wheel drive is, but there are a great variety of systems, and with open differentials on front and rear, you could have both the front right tire and the back right tire spinning on ice, and still be stuck. In that case you have two wheels trying, but not all four. There are limited slip differentials that add some power to each wheel and there are various sensor systems that detect slip and try to send power to an idle wheel.

That's a start. See what other say.

This explanation from a man who is rebuilding a differential on a rock crawler. ( with lots of little parts). So better listen to him.

There’s so much electronic “advancement” compared to the positraction rear ends and lockout front ends when I used to fool with this stuff that I’m not qualified to comment.

I pushed the button on the Highlander to back through a 150 foot mud hole in Ontario last July after it rained for two days and I backed right out onto the road. I like the button. Four inches of rain here in the last couple of days, probably a lot of people using the button.
Iowa Dave

[Brian B-P]

Originally Posted by gbaglo

My RAV4 has a button you push to lock all-four wheels. Never pressed it, but I assume power would be applied to all the wheels equally.

No, not equal power - equal speed. The system applies engages a clutch to drive the rear wheels (the front wheels are always driven) and the traction control feature applies brakes to wheels individually to keep them all turning the same speed.

[oldwave]

I have a two wheel drive truck and a 21 . I have had three or 4 instances in the last 3 years I wish I had the 4 wheel drive.

[Doug2000]

Some people in the Deep South May get away with 2WD, but most need 4WD. This one time I got stuck in my campsite with my minivan. My tent trailer was really big, Fleetwood 14’ box, the site was at the bottom of a hill. The neighbor had to give us a tug with his F250, 4WD of course.

[WillyB]

I have a 2016 F150 4x4 with a locking rear diff.

From a practicality standpoint I’ve used four wheel drive 2 or 3 times in snowy weather for traction and control purposes. I’ve used the rear diff lock 8-10 times at boat ramps, slippery grass slopes pulling into my secret fishing spot and for a small section on my road to simply keep the rear tires from spinning and making ruts.

Rear diff lock is for those occasions when you need a quick little traction boost. Four wheel drive is when you need a lot of traction for a much longer period.

If you’re not concerned with driving in hilly snowy areas the rear diff lock will give you that spot traction you need for your 2 wheel drive. Like I said; boat ramps, slippery grass slopes, etc...

Love the rear diff lock.

[salmo7000]

My Chevy Colorado has 2WD, automatic AWD, then it can be locked into full 4WD high and low. This seems to offer all the options. One thing I will say, particularly after the trip I just returned from, I would not tow without the option to put the vehicle in 4WD. I had no problem getting TO my campsite in eastern Montana in 2WD, which involved 10 miles on a dirt road. But it rained hard the night before I left, and I’m here to tell you I would have never made it back out that road without 4WD. The road got incredibly soft, even with a good layer of gravel.

Then later in the journey home, I hit 5” of snow on Roger’s Pass, which included a crosswind blowing it into drifts and a notable absence of any snowplows. This was just last Monday, mind you, and it had been in the high 90’s prior to this cold front. It never occurred to me I would be towing through snow on this trip!

I guess it depends on where you think you might want to go and what weather conditions you might expect, but for me, there is no way I’d be caught without 4WD, or without chains for that matter. I just don’t want to get stuck!

[gbaglo]

Might want to consider resale or trade. Are the dealerships full of 4X4s in your area? Do most people want 4X4 or 4X2?

[Centex]

Originally Posted by Doug2000

Some people in the Deep South May get away with 2WD, but most need 4WD.

I'm compelled to point out that literally millions of miles of happy RVing far beyond the 'Deep South' have been enjoyed by folks driving 2WD tugs over many, many decades.

4WD tugs were not that common at all during the decades that my parents were very actively Airstreaming from the old Alcan Highway to Nova Scotia to interior Mexico and all points in between. Logging several hundred thousand miles themselves, they and the majority of their counterparts towed with International Travelalls and Suburbans (this also the era when crew-cab pickups were rare among RVers and 'supercabs' hadn't been conceived), almost all 2WD like my parents always owned, equipped with simple 'limited slip' differentials, not even a 'locker'.

Lots of us don't venture seriously 'off-road' (though we do venture off-pavement), lots of us don't drive in snow, lots of us don't find those factors limiting in our travels, and lots of us have never gotten ourselves 'in-a-bind'. I'm among that group, towing with 2WD / limited-slip pickups, F150-250-350, for well over 20 years and enjoying every minute of it.

You can get yourself 'in-a-bind' with 4WD, there's no shortage of anecdotes relating those occurrences.

"Need" is a function of use-habits (and judgment in use), and those can vary significantly among the RVing population.

Just sayin'

[steve dunham]

I’ve only used my trucks 4 wheel drive once when camping but in the winter when heavy snow falls It’s saved my butt on many occasions.

[John in Santa Cruz]

Good all terrain tires are just as important as 4wd, maybe more so. I was on a 20 mile fire road run with a friend in his tundra 4x4 that had highway tires, I was in my Tacoma 4x4 that had BF Goodrich ko2 all terrains, he was in 4x4 and spinning his wheels, I was in 2x4 and had perfect traction the whole way. Note neither of us were towing nor did either of us have a particularly heavy load, just some telescope gear that we were hauling to the top of a mountain.

there have been several places where I've had to use 4x4 on dry pavement when towing that very low speeds and a steep grade like a driveway, startup it with the truck and spin a tire. Stop, switch it into 4x4 and just roll up the hill in first gear

[Steveanson]

The only time I use my 4WD is on slippery slimy boat ramps or driving in the sand at Surfside Beach and South Padre Island. I have pulled our Casita and later a Forest Junker err River up and down BLM fire roads and national forest paths, never slipping into 4WD. I live in coastal Texas, and because of many of our adventures won't do without it. Matt & Pat

[sherminator]

I have a full-time locking rear diff on my 2wd Ranger - which gives me two driven wheels on the rear axle, and conventional open diffs on my 4wd F150 - which gives me a driven wheel on the front axle and a driven wheel on the rear axle. Here is my experience with (and without) towing the same 2000# tent trailer:

2wd Ranger: The rear tires chirp a lot when giving it power while making sharp turns - think leaving a gas station and going into traffic. In slippery conditions, if one rear wheel has good traction, I'm good to go. If both wheels lose traction, my rear end jumps sideways immediately - much faster than an open diff 2wd. I really have to take it easy on turns in the snow. It helps a lot to have weight on the rear to get better traction.

4wd F150: 99.99% of the time I drive it in 2wd and it behaves the same as any vehicle. The great majority of my 4wd use is when I am backing my trailer into its spot on the side of the house, which is up and across a grade on gravel. If I leave it in 2wd, I spin the rear tire and usually come to a stop. Since my front wheels are on concrete during the steepest part, I switch to 4wd and reverse the trailer up the grade and around the corner nicely and under control. With the Ranger, I often slip on the gravel, my rear end jumps sideways and jacknifes the trailer. I then pull forward, gun it up the grade in reverse and around the corner less nicely and with less control.

My conclusions: 2wd with a locker is better than no locking diff. 4wd with open diffs is better than that. 4wd with an electronic locking rear diff would be the cat's meow. It all really comes down to traction. If you can get at least one driven wheel on a spot with traction, you will get where you want. My Ranger works well with my tent trailer, and I am happy with it. I will be using the F150 on the Escape, and will be happy with it. The real key is to drive to drive within the capabilities of your rig. The driver is really much more important than the rig.