Click for Coverage
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

September 2009 4x4 Truck Repair Questions - Techline

Posted in How To: Tech Qa on September 1, 2009
Share this

Where To Write
Address your correspondence to:
Four Wheeler
6420 Wilshire Blvd.
Los Angeles, CA 90048.

You can also reach us by e-mail at; be sure to type the words "Tech Line" in the subject line. All submissions become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Random Beeps From LJ Rubicon
Question: I have a 2006 Jeep Rubicon LJ with the six -speed and 4.0L I-6. I get a random beep from inside the cab, but only when I have my headlights on. The beeping sounds just the same as if I was holding the e-brake on. I'm about 99-percent sure that it is caused by the ARB bumper I have on the front. I have the marker lights on the ARB wired up to the outside marker lights on the fender flares. I went over the wiring, and everything looks good there. I also noticed that one of my turn signal arrows on the dashboard sometimes glows/fades on and off during night driving. Also, if the beeping starts, the only way I can get it to stop is either turn off my headlights, push my hazards on for a second, or use the turn signal of whichever side marker arrow is glowing (this changes from left to right). Sometimes I can drive for a half hour without a problem, but sometimes it does it like every 30 seconds. I'm pretty sure this is some kind of voltage problem, but I can't solve it.
Lake Villa, IL

Answer: I don't have a clue, but the first thing I would do is disconnect the marker lights on the bumper. If the noise/light problem goes away, then problem solved. New vehicles use the same wire in a lot of cases to move different signals to different locations. It's beyond my ability to explain how this works, but it does. The added current draw from the marker lights may be causing a false reading and the problem. Easy to find out.

Second, I would look for a corroded electrical connection, either at the spot where the wires plug in or at the bulbs themselves. Again, a higher voltage draw. I did check for any Technical Service Bulletins and found none on this kind of problem.

Please do let me know how you solve the problem. Perhaps it will help someone else.

Careful With That Axe, Willie
Question: I think Willie Worthy's list of boonie trail tools (May '09) did not include the axe required by the Forest Service. I prefer the Pulaski as it also helps digging out the tough stuff from under the rig or to set a "dead man" when the winch line is too short. I also feel naked without heavy-duty chains for all four, having grown up with two-wheel-drive ranch trucks. Easing through the steep, rough, slick stuff with the iron down saves wear and tear on man and beast. Good article.

Answer: The Forest Service in Montana does not require an axe. In fact I am reading this right now from a USFS publication, "Attachment C, Forest Fire Rules and Regulations." For a campfire, they require a bucket holding at least one gallon of water, and a shovel with a point and a minimum overall length of 24 inches. If using a chainsaw, a minimum of a 4BC-rated fire extinguisher as well as a pointed shovel with a minimum overall length of 36 inches is required.

An axe is kind of a useless tool, as most people don't know how to use them properly anymore and they are usually dull. A Pulaski, on the other hand, when used properly and sharpened properly, is an excellent tool. I feel that a LHRP (Forest Service speak for Long Handle Round Point) shovel with the edges sharpened is a very useful tool to have. Besides using it as digging tool, it can be used to "smash out" small fires, toss dirt, and the sharpened edge can cut brush. To my knowledge, very few, if any, national forests require an axe. I do believe that it used to be a requirement, but not any longer. For those of you living in other states, you might want to double check with your local national forest office as to the rules.

I don't agree with you on chains, but there may be places that you go that they work just fine for you. One of the facts about driving in mud is that wheel speed is important in cleaning out the tire tread. However, wheel speed and chains just don't get along. I try to stay off of muddy roads and trails as much as possible because I hate cleaning up afterwards, and secondly, it just doesn't do the road or trail any good.

As to using chains on a non-muddy trail, well, depending on the rocks involved, it's a quick way to destroy the chains, and on most trails the chains don't leave a very nice footprint but tend to damage the land. In snow, sometimes chains do have their place, and I have often used them in the past.

Wants Hummer H1 6.0L Swap
Question: Hummer H1 woes here. Can you give me some info on replacing the 6.5 turbodiesel money pit/dog poo that is in my '96 H1? I'm checking out the 6.0L Chevy gas motor-it has good brake horsepower and comparable torque. Do the blocks share the same bolt patterns to the bellhousings? If they do, the rest is no problem. If they don't, can I buy a bellhousing or an adapter kit to connect to the 4L80E transmission? Or is there a better motor to use (that's modern)?
Brian Hopson
Waterborough N.B. Canada

Answer: I have never heard of anyone doing this swap, nor could I find any information or even a hint of information on it.

OK, here is what I think, and it's not to be taken as gospel. (Hopefully, some reader has either done this swap, or can point us to a source of such a swap.) The Hummer is big and heavy, so it's going to take a lot of motor to make it perform. My choice would be an 8100-series motor instead of the smaller 6.0-liter. There should be plenty of room for it. The transmission should bolt up to it; however, the torque converter should be changed out to one from the gas motor, as it follows the torque and horsepower curve of the motor. How much of the wiring harness is interchangeable is a good question, and could turn out to be simple or problematic. One would want to get the complete wiring harness and all the components. Definitely you would want to use the transmission controller from the gas motor. Hooking up all the emissions equipment could also be a real challenge, as will convincing your local smog station that it will be in compliance.

Wants Stick Back In High-Boy F-Truck
Question: My wife just bought me a '77 F250 High Boy which has a 460 and an automatic trans that someone swapped in. How hard would it be to put the standard trans back in, and what transmission would that be?

Answer: To start off with, hopefully the clutch pedal assembly was left in the truck. Otherwise, that, along with the rest of the linkage, is going to have to be located and reinstalled. You are going to need a flywheel for the 460 motor and matching clutch disc, throwout bearing, pressure plate, and clutch fork. You will have to install a pilot bushing in the end of the crankshaft for the transmission input shaft to center on.

The truck originally had an NP 435 mated to a 205 transfer case, and it would be better and a lot simpler to find the two already mated together. Be sure you get the transfer-case shift linkage. Oh, and for a bellhousing, not a lot of 460s came with standard transmissions, but one from a 351M or 400 will bolt to the 460 block.

Late-Model Chevy Speed Sensor Issues With NP 205
Question: I'm in the midst of a solid axle swap on my 1993 Chevy 3500. I am going to run a Dana 60 front axle with the diff on the passenger side so I can use an NP 205 transfer case as opposed to the Ford Dana 60. My quandary is how do I get around the problem of the speed sensor reading the speed from the NP 205? Please save my garage walls from the trauma of continued head-pounding.
Chris Jensen
Riverside, CA

Answer: Call the guy who fixes the drywall-you no longer have to keep banging your head through it. Take a look at, and go down about three-quarters of the page to "Electronic Vehicle Speed Sensor." This guy had the same problem and figured out a way to fix it.

Letter Of The Month
Front Or Rear: Which Diff Is Strongest?
Question: A group of us 'wheeler types had a long discussion on the actual durability of the front differential on a typical 4x4. As the front is engaged after the rear doesn't (automatically) or is locked in by choice, most of us (three) felt that the front diff was probably inherently much weaker than the rear, as it does not need to be engineered anywhere as well as the rears. Nobody was willing to disconnect the shaft to the back wheels to experiment, so we felt y'all were the ones to ask. What say you?
Bobby Diesel
Crompond, NY

Answer: That's a really interesting question, as well as a good one. Generally speaking, the frontend of a 4x4 is not as strong as the rearend. In some cases, this really doesn't make a lot of sense to me, especially for someone who does some serious four-wheeling with large tires.

Historically, the front axle is always of, let's say, "lesser strength" than the rearend, but not always. For instance, most Jeeps, while using the Dana 25, 27, or 30 up front, used a Dana 44 in the rear. Fullsize Chevys used a 44 or a Corporate 10-bolt up front while using the very stout 14-bolt in the rear on heavy vehicles like the 3/4-ton Suburban. Early Scouts had Dana 30s up front and 44s in the rear, while the Dana 30/Ford 9-inch combination was used on early Ford Broncos. Later, both went to 44s up front to solve breakage problems. Ford did it one better than everyone else and used a high-pinion 44, so that the pinion was actually driving on the proper side of the ring gear. Then all the 1-tons went to Dana 60s up front, but again Ford did them better for a few years and used a high pinion. The Jeep JK Rubicon axles are Dana 44s on both ends, and the front is high pinion.

Going back a bit here, frontends are nothing more than a rearend turned in the opposite direction. This means that the pinion gear is driving on the back side of the ring gear, which has about 20-percent less strength (and no, you just can't flip over a housing and turn it into a high-pinion design). Jeep also saw the advantage and built XJs with high-pinion 30s for a few years. But why run the 60 in the front of 1-ton pickups when the 3/4-tons had the 44 but generally the same rearend? Most likely for weight-carrying capacity, as the 60 is a lot bigger with stronger tubes.

Now that we have that out of the way, let's look for a minute at why the manufacturers figured they could use a smaller and weaker axle up front. For more than 90 percent of its overall life, a 4x4 vehicle is used in two-wheel drive. When 4x4 mode is necessary, it's usually because of the lack of traction. Keep in mind that now the power is being driven to two axles, not just one, so in theory each axle is now getting only one half the of the engine's power, hence half the load. Does this mean that the front end only has to be half the strength of the rearend? Maybe so, but I am not enough of an engineer to determine this.

What I do know, along with everyone else, is that when climbing a hill the actual overall weight is being transferred to the rear wheels. That's pretty easy to figure out, as we can actually feel the frontend get light and sometimes even lift the tires off the ground. More weight equals more strain on that axle, hence its need to be the stronger one. When going downhill, the reverse is true, but the extra power needed-such as when going uphill-is not being applied to the front axle so it doesn't need to be as strong.

When you factor in what we are doing as recreational four wheelers, it's an all new ball game. There are many times when the load-that is, the overall weight-and power requirement to the front axle can exceed that of the rear axle. An example would be going down a boulder-filled canyon when the frontend encounters a major obstacle and needs to climb over it while the rear axle still rests on fairly even terrain.

There is also the cost factor. A bigger drive axle costs more than a smaller one, and while it carries more weight, it also weighs more. More mass to move means more fuel needed. So cost and fuel mileage are major players here. It comes back to the fact that for most people, the smaller size axle up front works out just fine

It would be nice to have an engineering degree and be able to explain it in engineering terms, but I don't, and well, can't. So that's the answer to your question in a roundabout way; it's the best way I can explain it so that it makes a bit of sense.

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Browse Articles By Vehicle

See Results