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Part 2, Better Traction on the Tow Vehicle of a Travel Trailer

Since the internet primarily offers infomercials and entertainment, it is difficult to find helpful information about four-wheel-drive and better traction. I had almost given up before finally bumping into this article, which serves as a primer.

Today's post is aimed at finding shrewd low-cost methods of getting better traction without being suckered into a high-cost pickup truck. Automobile manufacturers use the marketing gimmick of "bundling," and the weaknesses of the male ego, to raise the cost of a pickup truck into the stratosphere. 

This post is not aimed at:

1. A pickup pulling a fifth wheel trailer, which then is empty when you unhitch, meaning little weight on the rear tires.

2. A pickup used in town for getting groceries or hauling kids to school, and therefore has no weight on the rear axle.

3. Lowering a boat trailer down a boat ramp until the rear wheels of the pickup are sitting on ooze, algae, or moss.

4. Snow or dune buggy terrains.

5. Doing sharp turns on mountain switchbacks, a terrain best handled by 4WD with open differentials or by all-wheel-drive.

That is a lot of 'nots'! What it does pertain to is RV camping on (3 or 4 digit) dirt/gravel roads on BLM and national forest lands, with a pickup or van pulling a conventional "bumper pull" travel trailer. Here you have plenty of weight over the rear axle of the tow vehicle, including drinking water, tools, books, and the weight of the cap for a pickup truck. Therefore a rear wheel drive pickup truck won't get stuck on wet grass, as is true of the suburban driveway queens.

Traction problems are of two independent kinds, with only one of them benefiting from 4 wheel drive.

A) Front to back. This can only be solved by getting a 4WD or all-wheel-drive.

B) Left wheel to right wheel, on a given axle. Best addressed by a differential locker.

Example B) is what this post is aiming at. The typical situation on banked or crowned dirt roads, during the monsoon season, is loose mud on the right hand side ("starboard") of the tow vehicle, since that is where the ditch is. Meanwhile the left side ("port") is high and dry, with good traction.

Another typical situation is a muddy two-track which has random puddles here and there. Only one wheel slips at a time.

The last typical traction problem is the loose gravel coming out of an arroyo crossing. Admittedly this case may be more of a front/back traction problem, which is best for 4WD.

When your dominant traction problem is one wheel on any given axle, 4WD will not help much. What you need is a differential locker. They completely lock the differential, even if one wheel is up in the air! (Limited slip differentials are different than a differential locker.)

Alternative 1) Did you know that you can add the (electrical) eLocker differential locker by Eaton on a low trim level (work truck) F-150 pickup? The differential is "open" until you push a switch, at low speeds, to make it lock. You can also find low trim level Chevy Silverado work trucks that have a different differential locker, also made by Eaton. These are low cost ($400) options, as is the towing package. Why doesn't every half-ton pickup customer choose them? We know the reason: they think the half-ton pickup is just a passenger car that looks cool and macho. They are not interested in actually using it as a truck.

Generally manufacturers try to make you believe that you need the expensive premium off-road package, with all the trimmings, to get differential lockers. That way you will buy a $50000 pickup truck instead of putting a $400 option on a low trim level ($25000) pickup.

Alternative 2) The other way to address bad traction on one wheel is to use the traction control systems that are now standard on virtually all vehicles. They use the information from the wheel speed sensors to detect slippage in one of the wheels, and then apply brake pressure to it. They also back off the throttle. If such systems got good enough, differential lockers would be unnecessary for many customers, and campers like me might be the beneficiaries. I'm not sure that they are good enough yet, particularly after getting stuck. I would be interested in pertinent anecdotes from the reader.

There is almost a conspiracy of silence over this issue, since the automobile industry doesn't want people escaping their $50,000 driveway queens. But I finally found one good article by a Chrysler engineer about Jeep's traction control system. Presumably their system is even better on a new vehicle.

Alternative 3) Aftermarket lockers. Someone recently told me about how pleased he was with a low cost ($350 plus two hours installation) aftermarket differential locker called the True Lock. He added it to his 4WD Jeep and saw a day versus night improvement. But his Jeep was old enough to lack a modern traction control system. Would the latter get confused by the True Lock? Compatibility with modern control systems is essential for any aftermarket locker. Here again, the internet is too busy with infomercial and entertainment to explain this issue well.

Let's assume that compatibility exists. Where can you get an aftermarket locker installed? Presumably I wouldn't want to go to one of the upgrader/modifier businesses that caters to the hard core "enthusiast" crowd, at astronomical prices. What I need is a good mechanic who has experience with frugal traction-oriented customers.

You cannot expect miracles in all situations from this scheme of saving money with a differential locker on a 2WD truck: it won't help if the left rear tire and right rear tire have equally bad traction, or if you are slipping on a steep switchback, where a differential locker would keep you from turning sharply enough.


As I've said before, just spend the two extra grand and get a four wheel drive with lock-in and out hubs and be done with it already. The extra money spent amortized over the twenty some years you will keep the vehicle is negligible… and so is the 2 mpg less in gas mileage. It will open up unlimited boondocking options (subject to your trailer's clearance), and at the rate the old (secret) boondocks are filling up, that should be motivation enough. No matter what kind of traction control you put on a 2 wheel drive pickup, it will be only 10 % as versatile as a 4wd. And no, "maintenance" is not an issue. I've had 4 wheel drives for 40 years and never once had to do anything to the transfer case or the front end/hubs. Just bite the bullet and you will never be stuck again… even if it snows or rains a foot, tho you might need a set of those "quickie chains" in the absolute worst conditions.
1. I agree that 4WD need not be a maintenance item. After all, it is in 2WD most of the time.

2. Agree about fuel economy being a non-issue: new pickups are rated at over 20 mpg whether or not they are 4WD.

3. You neglected to mention that 4WD trucks have payload ratings 200 pounds lower than the equivalent 2WD, and for a half-ton pickup truck, that might matter some.

4. Agree that 4WD BY ITSELF is probably worth the cost, but not if it is the enabler of unscrupulous "Bundling" by the marketing department of the manufacturer.

5. It is always so difficult to discuss "practical" issues unless one makes it clear what kind of situation you are talking about. I thought that I had done that. I am not so much interested in steep switchbacked roads in the mountains; rather, I care more about loose or muddy roads in semi-flatlands as one approaches the mountains. That is where I camp: at the foot of the mountains.

And a 4WD with open differentials will get stuck when the front right and rear right wheels sink into the ditch on the right side of the road.
"And a 4WD with open differentials will get stuck when the front right and rear right wheels sink into the ditch on the right side of the road."
and that's when you lock in the front hubs…
and, you can get just as stuck, if not more stuck, at the foot of mountains than you will up in the mountains where there is generally more rock (as opposed to silt and sand runoff from the mountain).
Just my opinion
Well I don't claim to have all the answers. Still doing homework.