March 2008 4x4 Tech Questions - TechlinePosted in How To: Tech Qa on March 1, 2008 Comment (0)
Address your correspondence to:
Techline Four Wheeler
6420 Wilshire Blvd.
Los Angeles, CA 90048.
All letters 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 www.fourwheeler.com. Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.
Question: I have a '75 Ford F-250 four-wheel-drive with power-assist steering. I've heard that a GM gearbox is an easy conversion to power steering. Could you tell me what year or type of gearbox to use? My guess is a box from a '67-'72 truck, but I'm not sure.
Answer: Every year or so, I get a question similar to yours on how to solve the power-steering problems associated with the ram assembly on the early Fords.
One of the nicest kits I have ever seen comes from Benchworks Steering Systems (480/946-3992, www.benchwork steering.com). While on the pricey side, it has everything you will need so you don't have to go out searching for parts and pieces that may or may not be right. This complete kit includes a rebuilt 16:1 ratio Ford power-steering gearbox (14:1 is also available). Everything is included from the column to the steering arm on the axle-which means the intermediate shaft, gearbox, pitman arm, drag link, a bolt-on bracket to mount the gearbox to the frame, all the hardware, and factory-style hoses.
Question: I have a '92 Chevy K-2500 with the 350 V-8 and 4L80-E tranny. I just put a front differential in it. When it's on jackstands in two-wheel drive, the back tires move. When in four-wheel drive, all tires move. When in 4-Lo and 4-Hi, the tires are moving. When I shut the truck off, grab the front tire and spin, the front driveshaft also spins. However, driving down the road in two-wheel drive, the front shaft now spins.
New Kensington, PA
Answer: If you look on the passenger side of the vehicle coming off the differential case, you will see that there is a difference from the driver side. That is because there is a thermal-operated inner axle disconnect mounted here. When you shift into four-wheel drive, a switch on the transfer case directs 12-volt power to a heating element that in turn causes a gas to expand and pushes a shift fork that locks the axle to the differential. For whatever reason, your shift fork is constantly engaged. It could be for some reason that the switch that sends 12 volts to the thermal actuator is constantly on, but I kind of doubt it. More than likely someone didn't put things back together properly when the differential was replaced.
Question: I have an '88 Jeep Cherokee with the 4.0L Six. I want to put a Chrysler 440 V-8 and a TorqueFlite tranny in it. Is this realistic? Does anyone make motor or transmission mounts for this? Since I only use rear-wheel drive, what do I do with the front axle? Any other problems that you can see?
Answer: Well, anything is possible if you have enough time, money, and expertise. Before you even think anymore about this project, find a local used-car lot that has a '90s ZJ Grand Cherokee with a V-8 in it and take a good hard look. The engine compartment was designed for the V-8, and as you can see, it's a darn tight fit.
The Cherokee XJ's engine compartment is a lot smaller than the ZJ's, even though the front suspension is almost identical. You will find that the 440 engine is 3 inches taller, 4.5 inches wider, and a bit longer than the 318 that was used in the Grand, and it weighs in at 670 pounds versus the 318's 550 pounds. All of the components to do this conversion, such as motor mounts and radiator mounts, will have to be custom-fabricated, so it's not going to be an easy task. I have seen some small-block Chevys in XJs, and they are a pretty tight fit.
As to what to do about the front axle, well, I think that would be the least of your worries. Jeep actually offered the XJ in a two-wheel-drive version. The front axle was nothing more than a large piece of straight tubing with the steering knuckles and components from a 4x4 version. All the mounts and control-arm brackets are the same. If you can't find one of these axles, I would think that someone who is capable of installing a 440 engine in an XJ would also be capable of building an axle using the 4x4 components minus the axleshafts and differential housing.
Question: I work for Massachusetts Forest Fire Control and the truck that I use is an '08 Ford F-350. My question is regarding the shock mounts. They hang down 5 inches below the rear axle, which as you know, is useless for off-road driving. My truck also carries 225 gallons of water and various other tools. Would a lift kit handle this weight, and if so, what can I do with the shock mounts?
Three Rivers, MA
Answer: Yes, they hang down a bit below the axle, but most are held on by U-bolts, so just loosen them and rotate them up level with the axletube. Five minutes and easy to do, but it will limit how long a shock can go in there, even after the lift. I have come across some that are welded on, and for this it is still fairly simple to rotate them up, but some grinding and welding are required.
As to the lift kit, I knew just where to ask because I knew that Cage Off Road (866/587-CAGE, wwwcageoffroad.com) had some Super Duty trucks weighing 16,000 pounds serving in Iraq. I checked with VP Jim Cole, and he said that there should be no problem with that weight and their Cage Off Road Suspension lift: "I believe the F-350 has a load capacity over 5,000 pounds, so it sounds like he is right in line with the GVW. We build our bracketry out of 3/8- and 5/16-inch laser-cut plate steel for these heavy uses. The new one 1-ton trucks have a tremendous capacity, so it is important to build the lift components to match. We overbuild our product, strength wise, for those people who really go out and use their vehicle to its capacity, as we do ourselves."
I am sure that there are other companies out there that have also addressed this problem with their suspension lifts. Wouldn't be a bad idea for you to contact them directly and ask if their suspension kits are really up to maximum load capacity.
Question: While using my Warn 8274 winch in deep mud, my negative battery cable melted off the top of my battery. I use a two-battery setup: One for starting, and one for winching. Both batteries and isolator are behind the back seat of my Jeep. I use welding cable for both the winch and starter. The stud bolt melted right out of the top of the battery. What would cause this?
George Geyer Jr.
Answer: My guess is that you had a bad connection at the battery terminal/post that was causing a lot of resistance to electrical current flow in the form of voltage drop. Resistance produces heat. In reality, it doesn't take much corrosion to cause this. When the volts drop, the amp draw goes higher to maintain the same performance in watt usage (volts x amps = watts). You mentioned that you were winching out of deep mud. My guess is that you were working the winch near maximum amp draw. If you came close to the "stall point" of the winch motor, amp draw would be even higher.
I also checked this out with Steve Schoenfelder, a customer service rep with Warn, and he had the same opinion, as well as bringing up a couple more points: "Batteries behind the seats? They're a long way from the winch, and voltage drop increases with longer cables. Welding cable: what size? At Warn, we use 2-gauge for 6-foot lengths, and 1-gauge for 12-foot lengths. Is the cable sized properly for the distance from the battery to the winch? The cable connections should be crimped with the proper tool or soldered to the cable, not with cheap battery clamps."
Steve also brought up a point worth mentioning to other readers and one I have seen happen first-hand. You generally should never hook a winch to the side terminal of a battery that has both top and side terminal connections. The side terminals do not have a heavy-enough connecting strip to handle a high-amp electrical draw and can very easily melt right out of the battery case.
Question: I ran across a set of Dana 44s out of a '70s Scout for $400. Would these be a good upgrade for my '79 CJ-7? How much width would I gain?
Answer: The flange-to-flange distance on a Scout 44 is about 59 to 59.5 inches. I believe your CJ-7 is about 56 inches. There is a difference of about 3 to 3.5 inches, so that means track width will increase about 1.5 to 1.75 inches on each side, depending on tire size and rim backspacing.
However, before you just jump in and start on the swap, keep in mind that there are a couple of drawbacks to the Scout axle as compared to the Jeep axle that will become very apparent once you start the swap. Personally, I like the Scout axles and use them under my own Jeep. You just have to learn how to deal with them.
Let's start with the back first. You get some 1.31-inch-diameter, 30-spline flanged axles and some 11x2-inch brakes. Each axleshaft is the same length, so that makes it handy for only having to have one spare on hand. (OK, you should always run an axle in the same direction and not swap side-to-side, but for a "get-you-home spare," it's just fine.) However, what this means is that the pinion is offset and the driveshaft will not line up directly with the transfer case. Is this a problem? Not really, as long as both ends of the shaft are on the same plane and you don't have a lot of downward angle. I have run them like this for years without any major problems. Naturally, you're going to have to cut off and remount the spring perches at the proper width for your frame and correct pinion angle.
Now let's go to the front, where things get a bit more problematic. Overall, things look good. Big disc brakes (same as an early-CJ disc-brake setup), heavy eight-bolt spindles, and 1.5-inch-diameter, 30-spline axles. The Scout frame was wider than the Jeep frame, and you'll notice that the differential housing is quite stoutly braced, right where the spring has to mount on the right side. Plus, the offset is a bit different than what is on your Jeep. By the time you cut enough room for the spring to properly fit, you've weakened the housing quite a bit and you really don't have a place for an inside U-bolt. I have seen a lot of modifications done here, and none of them are very nice. What I've done on a stock Jeep frame is to put the front spring outboard of the frame, which means custom-built new spring mounts as there are no kits available that I know of to do this. While you're at it, you might as well do a shackle reversal. Even with the springs set at an outboard stance, the clearance is tight. OK, we're good here, right?
Now look at the steering knuckles. IH chose to make the steering knuckles quite stout and the steering arms quite long. Good thing about this is that it offers lots of clearance for the tie rod and differential cover when in a tight turn. Bad thing about this is that Scout also used a very long pitman arm off the steering box. Your present steering-box mounting location is too far rearward to allow clearance for the longer arm. Yes, the Scout arm will bolt right up to the pitman shaft on your present steering box. No, you cannot use the Jeep pitman arm-the shorter length of it will drastically prevent full left and right turning. So this leaves you with a couple of other modification choices. You can redo the mount and move the steering box forward for proper clearance, and have great steering. Or you can swap the steering knuckles for those off your Dana 30 front end-they are interchangeable. Please don't think that you can redrill the steering arms closer to the knuckle. I have seen some people do this but do not recommend it. There is really not enough material left around the hole. This makes for some marginal strength, and steering is not the place that you want to sacrifice strength.
Now comes the real problem. Scouts, because of the way the spring mounts and other factors, use only 0 degrees caster angle. I believe the '80 Scout used maybe 1 degree. Your Jeep was designed to use something like 5 to 7 degrees of caster angle. Remember, caster is pretty important, as it's what keeps you going down the road straight. OK, you set your spring pads to get the 7 degrees and then take a look at your pinion. It's pointing downward! The only way to correct this is a heck of a lot of work. You have to cut free the weld at the steering knuckles and rotate them, hopefully equally on both sides, until the pinion angle is correct, and then reweld them. Not an easy job. Dana did one heck of a good job of getting deep penetration on the welds. Believe me, it is one hard job. I made up a fixture to do mine in, and I believe I ended up rotating them about 15 degrees to get the proper pinion angle and caster angle for my application.
Still ready to make the Scout front axle swap? Maybe not? I am going to give you a second choice. Use a Jeep Wagoneer front Dana 44 axle. They are about the same width as the Scout axle and have the proper caster built into them. OK, they have six-lug bolts. Not a problem. Chris Overacker at Code 4x4 in Rifle, California, turned me on to this many years ago. You use a Ford hub rotor assembly from a '76-and-later F-150 (PN EITZ1102C) along with the Jeep wheel bearings and a Ford seal (PN C9TZ1175C).
One more thing: Just in case you come up with a screaming deal on a Wagoneer, you can use the rear axle too. Swap out the left rear axle for Jeep PN 994294, which is a 5-on-51/2 bolt pattern. (This may be an old, no-longer-used part number, but a good parts guy should be able to cross it over to the new number.) It's too long for the right side, so you will have to have someone cut it down and respline the end. Yes, I've seen people weld up a couple of the stud holes and have it redrilled to the proper pattern, but I think it's easier and safer to go with a new axle.