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April 2006 4x4 Tech Questions - Techline

Willie Worthy | Writer
Posted April 1, 2006

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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.

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