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November 2010 Nuts & Bolts

Posted in How To on November 1, 2010
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My First Jeep
Q I recently bought a '67 CJ-5 with a six-cylinder motor and a three-speed trans (for 700 bucks). I bought a new fuel pump and battery to get it started, but it runs rough. I don't know if the carb needs a cleaning or the motor needs a rebuild. When idling it misses, but once I rev it up it runs smoother but not perfect. I have a friend trying to tell me to pull it and put in a modern V-8, but that is costly and I don't plan on driving it that much to make it worth it. This is my first Jeep, and I don't know what I should do. What is your suggestion on making my Jeep drivable on the flat prairie and not an "over-the-top rockcrawler," as my buddy wants me to make it?
North Dakota Nick

A If this is your first 4x4 I'd suggest you fix the stock engine rather than swap in a late-model V-8. The V-8 swap is cool and will definitely give you more power, but more power will find the weak links in the rest of your drivetrain. Find a good service manual, buy some tools, and go through the steps of tuning up the old Jeep.

I had a '64 CJ-5 as one of my first Jeeps, and it was a great Jeep to learn on. The engine only needs fuel, spark, and air, so just follow those three leads. Is the carburetor leaking? Is the gas old? What kind of condition are the spark plugs, wires, and distributor cap in? Is the timing off? Does the fuel filter need cleaning? You can get that old Jeep running for much less money than tearing into it and swapping in a different engine.

Hi, Low & Reverse We Go
Q I have a question about high-pinion versus low-pinion in the front axle. I was recently attempting to pull out another truck with my '69 IH Scout 800A. It has Scout II Dana 44s, which are low-pinion front and rear. I hooked the towstrap to the front bumper, and some of the other spectators were expressing how hard that is on the gears in the diffs when pulling in reverse. I want to know which is the best way to pull with my low-pinion differentials and how they compare to high-pinions. Is there any truth to what these guys are saying? Is it best to pull in reverse with a low-pinion front? If I had a high-pinion front and a low-pinion rear, would it be best to pull from the rear? My International is pretty heavy on the front and gets great traction pulling in reverse, but am I damaging my gearset?
Myles K.
MooseJaw, Saskatchewan, Canada

A Yes, a low-pinion axle is usually stronger when driving towards the pinion, and a high-pinion axle is usually stronger when driven away from the pinion. As such, a low-pinion rear and a high-pinion front are strongest when the truck is driving forward. This is because the gear teeth have a drive side and a coast side, and the drive side is stronger than the coast side. When driven toward the pinion the low-pinion axle is on the drive side of the gear. Conversely, when driven away from the pinion the high-pinion axle is on the drive side of the gear. Some say that driving on the coast side of the gear can reduce strength by nearly 25 percent. When you have low-pinion axles front and rear, such as in your Scout, then either direction will have your truck running on the weak side of the gear in one of your axles. Though your reverse gear is usually very strong and low, I'd probably recommend pulling from the rear bumper if at all possible, as most trucks are designed to pull from that direction when towing.

Make a Good Deal Gooder?
Q I just bought a '98 Jeep TJ. I really wasn't in the market for another 4x4 but couldn't pass up this smoking deal. (I know everyone there at Petersen's 4-Wheel & Off-Road has been here before.)

Here is my dilemma. It has the severely underpowered four-cylinder engine with 94,000 miles. Would it be worth the time and effort to complete an engine swap for this vehicle or just try to sell it and attempt to find another Jeep with the 4.0L as clean as this? I know that with an engine conversion come headaches and multiple other drivetrain component replacements, but the initial cost I paid for the vehicle is far lower than any other Jeep I've seen. I am planning on this being a moderate trail machine, but I still want to be able to drive it on the street and meet California emissions laws.
San Diego, CA

A Swapping out the four-cylinder for the 4.0L six sounds good on paper, but it's not really worth the trouble. I'd say either drive it as is and put some low gears in it to turn bigger rubber, or sell it and find the Jeep with the engine you want. The four-cylinder isn't terrible in the dirt; they chug along pretty well. I know guys who love the 4.0L straight-six, but their rule is "the 4.0 is great in whatever it came in, but shouldn't be swapped into anything else." You would think the 4.0L would fall right into the four-cylinder Jeep engine bay, but I'm sure it's not that easy. If you had a good-running 4.0 and the four-cylinder was dead, I'd consider it, but since it runs now I would leave it alone.

Body Con Torsion
Q I have a '96 Chevy K1500 with the 5.0 V-8 and manual tranny. I just put on 265/75/16 tires on Pro Comp 16x8 rockcrawler rims, a Lund sun visor, Lund hoodscoops, and a brushguard. I thought I had it the way I wanted it and was finished buying stuff for it, but as soon as I dropped the jack my first thought was it could use a 2-inch body lift. You guys have more experience with them then I do, and I was wondering if you could lead me in the direction to a good kit. The lift is mainly for looks because it's pretty much my daily driver and wood hauler in the fall.
Justin W.
Bloomsburg, PA

A I think you should look into a torsion bar key leveling kit. While a body lift works well in many circumstances, the amount of lift is equal front and rear. With the leveling kit, you can raise your truck and level it out very easily, and one usually costs $100-150.

Right Jeep, Wrong Body
Q Hi. My son and I have purchased a '43 MB/GPW with a 1953 M38A1 body. The frame and powertrain are all original to the '43. We do not want to use the L-134 engine, but are concerned about what will fit in the frame without modifying the length of the frame.

We have to use parts from the junkyard because our budget is nonexistent. What will fit, either with an adapter to the T-90 tranny or a complete engine, tranny, trans case from a vehicle we can find in a junkyard?

My son is a mechanic and welder, and I am pretty good with my hands.

We are not planning on any rockcrawling or mud bogging. It will be used for deer hunting on logging roads in Idaho, and I would like to drive it to town or to work when the weather is good.
Mike B.
Athol, ID

A The M38A1 is very similar to a CJ-5. I think you would be better off either tracking down a CJ-5 frame and running gear or having your son build a new frame. The MB/GPW frames are fine in basic form and with stock engines. However, as you upgrade the engine you will find weak links in drivetrain and frame. If you decide to keep the MB frame I'd consider a GM V-6 like the 4.3L. It fits in the frame without too much work, offers good power for the Jeep, and is easy to find parts for. I suspect you can find a Jeep restorer who would be willing to trade a later CJ-5 frame for your MB/GPW frame with all the drivetrain intact.

Nuts, I'm Confused
Body Flex
Q I purchased a '97 Jeep Grand Cherokee so I could go wheeling with my friends and bring my family along. Everywhere I went, everybody gave me the same response: "Ooh, how's the body flex on that?" I always gave the same answer: "Not bad at all."

I had never experienced or even considered this problem until I pushed my limits on some terrain I probably shouldn't have been on in a stock vehicle in the first place. I was wondering if you could explain what body flex is, how it happens, and how to prevent it. I knew I had it coming to me when I bought a unibody anyway; my friends will never let me live it down that I bought a "fake" Jeep. But it was practical for me!
Muskegon, MI

A Nate, I think you can already answer the question. Unlike with some of the very first XJ Cherokees, I don't think body flex is nearly as much of a concern with Grand Cherokees and later Cherokees as it used to be. Body flex is the twisting of the unibody under hard off-roading, which can cause doors to be hard to open or close. In fact, most of the body flex problems found in unibody Cherokees are duplicable in many 4x4s with frames. I've seen huge 4x4 vans, trucks, and such that had bodylines all distorted from being four-wheeled.

I bet your Grand Cherokee is much stiffer overall than an original flatfender Willy's jeep, which has a frame made to flex and twist. Plus you can tell your hecklers that a unibody is very similar to a tube buggy, only instead of using tube yours is made of sheetmetal. Many professional race cars are unibody designs, and by using sheetmetal (or carbon fiber) they keep the weight down. There are various body stiffeners on the market, as well as upgraded suspensions, body armor, and performance mods for Grand Cherokees, so drive your truck with pride. In fact, the Grand Cherokee has won just about all of the 4x4 of the Year competitions it entered here at Petersen's 4-Wheel & Off-Road magazine. Not too shabby.

The biggest issue with the unibody is that when you try to do an engine swap or custom suspension, the sheetmetal subframe isn't nearly as thick to weld to as a separate frame. But when you consider that there is that elusive '98 5.9L Grand Cherokee out there with 360 ci of power under the hood, I'd say just find it rather than swap in a different engine.

I salute you for driving a 4x4 that is practical for your lifestyle, and for taking your family along when you go four-wheeling. What better way to keep the sport moving forward? I'm choosing you for this month's Nuts, I'm Confused award and will send you the final voucher for a set of tires from General Tire.

General Tire has been supporting our Nuts & Bolts section for the past few months, and we send a big thank-you to them for rewarding our readers with great prizes. We'll be back next month with a new prize, so keep writing in. And to order your own set from General Tire, check out

Submission Information
Confused? Email your questions about trucks, 4x4s, and off-roading tech using "Nuts, I'm confused" as the subject and include a picture (if it's applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file. Also, I'll be checking the forums on our website (, and if I see a question that I think more of you might want to have answered, I'll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes.
Write to: Nuts & Bolts, 4-Wheel & Off-Road, 831 S. Douglas St., El Segundo, CA 90245 fax to: 310.531.9368
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