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April 2006 4x4 Tech Questions - Techline

Posted in How To: Tech Qa on April 1, 2006
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Four Wheeler
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Question: I am embarrassed to say this, but I have a problem that I can't solve. Why I am embarrassed is that most of the guys in our 4x4 club come to me for answers to their vehicle problems, but I have one that I can't solve, and it's on my own vehicle! I keep having to replace the ignition module. I have gone through like three of them now. They will work for a while, and then the spark just goes away. I put a new one in, and the engine fires right up, but it only lasts a month or so and it dies. Luckily, I know the guy at the parts store so he keeps replacing them. Am I getting bad modules? Should I try another brand? I've checked all the grounds, cleaned them, and used dielectric grease on all the electrical connections.
Name withheld by request via

Answer: I doubt that you've been getting that many bad modules. Checking and making sure all the electrical connections are good is an important step. How about the engine-to-frame ground or the body-to-frame ground? These are very important, and ones that most people don't think much about. However, I figure that you already did this.

OK, my guess is that you have a red light for a charge indicator instead of a gauge. I would suspect the alternator as being the culprit. Excessive voltage or a weak diode that is sending unrectified AC voltage to the module will quickly destroy it. Change out your alternator, and I will bet that the problem will be solved.

Question: I have recently bought a set of Rockwell axles and shortened the long-side axletube. I am wondering, what's the best way to refill the closed knuckles with grease? Is there a certain type of grease I should use?
Josh via

Answer: I don't have any experience with the Rockwell axles, so I went over to the other camp where John Cappa, editor of Jp Magazine, hangs out, and asked him because he has a set of Rockwells under his J-truck. John tells me that there are three ways to lube the steering knuckles. If the axle is being disassembled, just wipe out the old grease and pack in new. Then reinsert the axleshaft. Kinda like packing a Toyota Birfield. If you ain't taking it apart, you can grease the crap out of the kingpin grease fittings (the upper and lower have fittings). These grease fittings ultimately feed into the knuckles after the kingpin bearings. There are also hex-head plugs on the ball ends-3/8-inch NPT, I think-right next to the rubber boots at about the centerline. Most of the time you can't tell that they're there because they are packed with grime. There is one on the front and one on the backside of each ball end. Unscrew the plug, thread in a large grease fitting, or shove the grease gun head in there and pump away. Each knuckle will hold about two tubes of grease if empty.

Question: I recently bought a '98 Jeep TJ with the 4.0L six and a five-speed. It has 140,000 miles on it, and since it was bought over an online auction, I have no real records of the vehicle, other than it's from Pennsylvania.

I am fairly sure I have an electrical problem but don't know what to do about it. Anytime I drive it on a cool morning or through any cold air, the gauges will all go to zero. If I tap the brakes, they will usually pop back on. If I let it go, they usually come back after a few minutes. What am I to do?
Bruce Dirden

Answer: I would think that would be very scary buying a vehicle like a Jeep from an online auction, not knowing its real condition. Hopefully you got a good price on it.

Usually, intermittent problems dealing with the electrical system are caused by a bad ground. You didn't mention any starting problems, so I will assume that the battery cables are clean and offer a good connection at both ends. Make sure that you have a good clean ground between the frame and the engine. I'm not exactly sure what Jeep uses for a bonding strap between the body and frame, but I suggest you look around and see if you can locate it and make sure it has good clean connections. Or you could run another strap or wire between the body and frame, just to make sure of a good ground. If this doesn't solve the problem, then maybe it's time to start looking at a factory service manual and trace the power feed to the gauges and see if something is amiss.

Question: I have a '72 Chevy two-wheel-drive longbed and an '84 1-ton GMC 4x4 that has a Dana 60 front and a Corporate 14 rear axle with 4.56:1 gears. I was wondering which way would be the easiest to make the '72 into a 4x4? I was thinking about swapping the cab over to the 4x4 frame, or would it be easier to swap the suspension under the two-wheel-drive? I love to go four-wheeling on the weekends, and I use my truck as a daily driver. I am on a tight budget, so the cheapest way would be best.

Answer: Most likely, the best and-maybe in the long run-the easiest way would be to swap bodies: That is, put the '72 body on the '84 frame. This way, you don't have to deal with driveshaft issues that may appear due to differences in wheelbase, or worry about drilling mounting holes in the '72 frame for spring hangers and such that may not be in the right location. Besides all that, you're getting a much stronger frame to match that heavy-duty running gear.

Without a doubt, there will be some body-mount issues to deal with, as I am sure the timespan of 12 years will have made a difference in mounting locations. That shouldn't be a real problem. There also maybe be a transfer-case body clearance problem that can easily be fixed by slightly raising the body off its mounts or some creative hammer work. New body mounts are going to be in order anyway, as the factory rubber will have compressed and broken down over the years.

Question: I've got a '95 Jeep ZJ with the 318 V-8. It was mildly built for 'wheeling (3 1/2-inch Rubicon Express lift, limited-slip in the Dana 35, 4.10:1 gears and 31-inch all-terrains for street driving). However, I now have an '80 CJ for the hard 'wheeling, so the ZJ is now serving as my tow vehicle. (It's not ideal, but it's what I can afford right now.) The radiator and thermostat (now a 185-degree unit) were replaced two years ago. The ZJ does pull that load pretty well; however, with the outside temp around 75 to 85 degrees, and trying to maintain 65 mph and the overdrive off, the engine temp wants to climb to 220. The only way to keep the temp around 210 is to slow down. Is there something I can do to bring the temp down? Is 220 OK? It seems high to me.
Joel Gabler

Answer: First, I believe you're running the wrong-temperature thermostat. I believe it should be around 195 or so, maybe higher. Check your owner's manual. If the water temperature is too low, the computer will make the fuel mixture a bit richer, which in turn will affect fuel mileage and possibly activate a trouble code light when not towing. Yes, I too don't like 220-degree water temperature, but it seems my own V-8 Grand always runs in the 200 to 210 range, even without a load, and it gets close to the 220 range when pulling.

Make sure the electric fan is coming on. This alone will make a huge difference in temperature control. Other than that, I would just say live with it. As a precaution, I run a quality full synthetic oil and change it at the 3,500-mile mark-or sooner, depending on driving history. Synthetic has a much higher tolerance to high temperatures, and with less friction, it may even help to lower the overall water temperature.

Question: I have a Suzuki Samurai that has Toyota axles front and rear with lockers and 5.29:1 gears. I have a 302 H.O. V-8 from a Mustang that I am installing over the winter. My dilemma is what transfer case to use. I want to run a C4 or a C6 automatic, and want to run an NP205, but don't know if a GM or Dodge case will work with the trans (passenger-side front differential).

Is there a way to install one with an adapter, or is there a specific case to look for? I do know that Advance Adapters makes an adapter for the C4 to a Toyota case, but I feel the 205 is more durable. I would also rather run a C6 for the overdrive.
Will Snider

Answer: While the 205 is an extremely strong transfer case, it has a couple of undesirable traits for your application. First, it's big and heavy and will take up a lot of room between the framerails, and maybe even won't fit between them. Secondly, it only has a 2:1 low-range gear, which isn't the most desirable for serious four-wheeling.

I would suggest that you see if you can find a right-side-drop NP207 'case or a Jeep Dana 300 transfer case, as these are a lot lighter, plenty strong for your application, and have a 2.72:1 and 2.62:1 low-range gear, respectively. Either one can be adapted to the Ford transmissions, and in fact take the same adapter plate. I would go with the C4 due to its overall smaller size-and by the way, the C6 is also just a three-speed without an overdrive. You could use an AOD four-speed overdrive automatic, which is really a good choice because you get a lower First gear than the C4 has, as well as a 33 percent overdrive. Both Advance Adapters and Novak have what you need to make it happen. If you do go with the AOD transmission, be sure to have a transmission shop show you how to adjust the TV cable. It's an important part in keeping the transmission alive.

Question: I have a '98 S-10 with a ZR-2 package with independent front suspension. I was going to install a 6-inch suspension lift and a 2-inch body lift, but I was told that the IFS was not worth spending money on, and the total amount would be around $1,800.

Others suggested I swap out the IFS for a straight front axle and then spend the money on the lift, which would be cheaper than lifting the IFS. Which would be smarter to do and stronger in the long run?
Joe Lott
O'Fallon, MO

Answer: I wouldn't say that the IFS isn't worth spending money on. Yes, articulation is somewhat limited when compared to a custom solid-axle conversion, but what you would lose is ride quality. Depending on what solid axle you would use for the conversion, frontend strength most likely would be increased. Superlift makes an excellent 6-inch lift kit for the truck, and yes, the price is about $1,800. Combine the suspension lift kit with a 2-inch body lift, and you can run 33-inch tires with plenty of clearance.

But the $1,800 is just a starting point. The installation cost is going to be pretty darn steep. Superlift estimates about 12 hours of time to do the swap. That's with an experienced shop doing the work, i.e., one that has a lift and all the proper tools. This isn't something that the average guy wants to take on himself. By the time you add on the $800-plus of labor for the suspension lift, plus another $250 in labor for the body lift and kit, you're looking at something like $2,800.

However, a straight front-axle conversion isn't going to be cheaper. In fact, it may be a lot more when it's done. First off, you've got the expense of the complete axle assembly. Price will depend on what model you use and if it's a high-pinion or low-pinion design, and what internal components you plan to use. If you want it to be the same width as your stock setup, it means a custom-built unit. You'll have to redesign the suspension system, which will involve new springs and shocks as well as a new steering system with proper geometry. A leaf-spring setup would most likely be the easiest, but you could also use coils or coilovers.

I'm not trying to talk you out of going either way, but just want to give you an idea of what you're getting into before you get started. I've seen a lot of people jump into a project and then be unable to complete it, either due to lack of money or lack of skill.

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