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March 1999 Your Jeep

Posted in How To on March 1, 1999
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Searching For Stock
I have a '48 Jeep CJ-2A and have been trying to find the stock tires for it. The tires have a 16x6 nondirectional tread like the military style, and they work great in the mud, which is important where I live. Do you know of any sources?
Ben Conrad
Halifax, Nova Scotia, Canada

Most people want bigger and better tires on their rig unless they're restoring it, but the tires you describe are a perfect match for your little flattie. The NDT (nondirectional tread) tires are available from many sources, such as Desert Rat Off-Road Center (Dept. 4WOR, 3545 S. Richey Blvd., Tucson, AZ 85713, 520/748-9299). The straight-bar, nondirectional concept means you can back out of whatever slop you got yourself into since the tires bite going forward as well as backward. The small diameter and cross-section of the tire also mean less stress is placed on the relatively weak Dana 25 front axle and Dana 41 rear axle, resulting in less breakage.

YJ-7 Hardtop?
I've been told that the CJ-7 and the YJ Wrangler use the same body tub. If this is true, can I use a CJ hardtop and hard doors on my YJ? I've been having a difficult time finding a used hardtop and doors for my '94 Wrangler for the wintertime, and this seems like a viable option.
Del Taylor,
via e-mail

This is one of those questions that elicit yes-and-no answers that can't be fully explained in less than three volumes, but we'll give you the basics: The CJ-7 and the YJ share a considerable amount of interchangeability, but are in no way the same tub. However, in regards to your specific question, the hardtops are somewhat interchangeable. The actual dimensions of the doors and tub are the same, but different variations of the '7 doors and tops make some of them poor candidates for the swap you're considering.

When the first CJ-7 hardtops were introduced, they featured a lever-style exterior handle for the door. The inside latch is similar to a regular latch on a screen door, which hooks to the inside lip of the body when the door is closed. The body tub of the '76-'80 CJ-7s use this style of latch, but the heavy, steel full doors flex the body considerably, causing the spot welds to break and the body to separate near the wheelwells.

Later CJ-7s and YJs have a paddle-handle on the outside of the door and a rotating-style latch, which engages a stud sticking out of the body tub. These later tubs have a different body reinforcement for the stud, and are much stronger and fatigue-resistant. Early CJ owners who want to use the later paddle-style doors need to weld in the reinforcement and install the stud. For your Wrangler, if these parts are in place, the later paddle-handle-style doors will work fine.

The actual fiberglass top from a '7 will fit the YJ, even down to where the bolt holes in the body line up and the screws in the windshield frame attach. The only real problem is the liftgate on the top versus the tailgate on the tub. The CJ-7 tailgate folds down, and the YJ swings sideways. The liftgate on the two different tops is cut differently to allow the gates to function with the liftgate closed, but when top-swapping is done, some interference occurs. The easy way is to trim or fill the liftgate to fit the body, but it isn't really necessary. Simply closing the tailgate before the liftgate is all you need to do, unless a spare tire is in the way. In this case, the liftgate of the '7 top and the tailgate of the YJ need to be closed by meshing the two at the same time, so the spare tire clears the liftgate.

Running Interference
I just finished putting on a 1-inch body lift and a 1-inch transfer case drop on my '84 CJ-7, which is this T-4 manual transmission. When I try to shift into Second or Fourth gear, the shift stick won't engage the gear, because the stick hits the body. Is there anyway to remedy this without cutting the floorpan, such as installing an altered shift stick? What if I use a CV-style driveshaft and take off the transfer case drop?
via e-mail

When you're installing a small body lift or a transfer case drop, the shifter will usually work fine. However, combining the two causes the transmission to move too far from the body, and the angle of the stick causes it to hit the body before it goes into gear. As far as we know, no one makes an altered shift stick for your Jeep, which means you have to modify it yourself or have a qualified shop do it.

Modification of the stick usually entails the stick being removed from the transmission, heated up with a torch, and bent in a few places so that it will clear the floor in Second and Fourth gears. It's usually easier (and cheaper) to trim away the sheetmetal on the floorpan to gain the same clearances.

If you want to raise the transfer case skidplate back to where it belongs, a CV-style driveshaft in the rear will help alleviate a poor driveshaft angle. For a CV shaft to function correctly, however, the axle end U-joint of the driveshaft needs to have a zero angle, rather than an angle equal to the transfer case, as before. That means adding or subtracting degree shims under the axlehousing to properly align the shaft.

Cherokee Dilemma
I presently own a '95 Jeep Wrangler that I love except for the nonexistent cargo area. Because of this, I'm looking to buy a new Cherokee, but I have a few questions. Will the unibody construction of the Cherokee handle medium-duty off-road chores as well as the Wrangler? In other words, will the Cherokee experience fatigue quicker than a Wrangler, and can it handle rock impacts as well as a regular frame? I need the roominess a Cherokee provides, and I'd hate to go look at a truck since Jeep doesn't build them anymore.
Marcos E.
Montreal, Quebec, Canada

The Jeep XJ Cherokee has been around since 1984 and is still one of the toughest vehicles. We've never seen any problems with the unibody construction in stock configuration, but with the addition of lift kits, larger tires, and more powerful engines, the unibody construction can experience fatigue problems, although it is uncommon.

The upper and lower brackets, which locate the locating arms onto the body, are rather beefy, and hold up quite well. Aftermarket arms are usually stronger and stiffer than factory offerings, which absorb some stress rather than transmitting it to the bracket. We've seen these brackets fail, but it was on a Jeep that ran 35-inch tires and was subjected to constant radical rockcrawling. For your type of use, we doubt you'll ever have a problem.

As to the frame-or the lack thereof-a unibody may be able to resist light-duty hits better than a conventional frame, since the sheetmetal will give a little and allow the body to slide over a rock. However, after years of use, it will be mangled and torn. A regular frame will only show a few scratches from the same rocks.

Shake It Up
My '94 Jeep Wrangler has a five-speed tranny and a 4.0 engine. I've added a Borla header, Flowmaster exhaust, and a K&N air filter.

My Jeep has a 4-inch Skyjacker kit with 33x12.50 BFG tires. My problem is that when I start off, the whole Jeep begins to shake. I've checked the U-joints, motor mounts, transmission mounts, driveshaft angles, and rear U-bolts, and everything is OK. I don't know what else to do about this problem, and I'm getting tired of the shifter jumping around in my hand. How can this be fixed?

In your list of modifications, you didn't mention a gear-ratio change, so we have to assume you didn't make one. If that is the case, you're having to slip the clutch to get the Jeep moving because the stock gear ratio is too high. This would be our first guess if there wasn't a problem before the tires and lift were added. The gear reduction needed for smooth engagement just isn't there and it needs to be for optimum operation.

Conversely, if the problem was there before, you may have a warped flywheel or clutch assembly, which could cause chattering when you let it out. Try putting the transfer case in low range and let out the clutch while you're in First gear. If there's no chatter or shake, the clutch is probably fine, and the reduced gear ratio is better for the big tires. Of course, this also means you should change the axle gears for a lower ratio.

You also mentioned that you checked the transmission and motor mounts, but the shifter was jumping around in your hand. A little movement is normal, but violent changes in direction means that the torque reaction mount may be worn-out or missing. This mount is two small pieces of rubber on a stud that's attached to the skidplate and the transmission mount adapter. This mount restricts the rotational movement of the transmission, and, without it, the shifter stick will bounce around a lot as the engine torque moves the transmission. Check this mount before spending money on gears or clutches.

Fender Banging
I recently noticed that after one of my more extreme trail rides, the tops of both of my YJ Wrangler fenders are dented downward. I have a 1 1/2-inch body lift and a 3-inch suspension lift and run 33-inch BFGs. The dent is in-line with the center of the wheel and is about fist size, yet shallow. I looked for any other evidence of fender damage, but found nothing. I looked at other club members YJs, and some of them have the same damage, with a variety of different lifts. What is causing these depressions?
Shawn Hughes
Vernon, British Columbia, Canada

You're not the first-or the last-person to get depressed over these depressions. If you check carefully, you'll probably notice the outer lip of the fender where the flare attaches to it has some slight wear marks in the center, that are in-line with the center of the wheel. What happens is that the tire contacts the lip on maximum suspension compression, pushing the outer edge upward enough to pull the center of the fender downward as the sheetmetal stretches.

Smaller tires or larger bumpstops can prevent these dents by keeping the tire away from the fender. Another solution is to trim the fender where the tire hits. Other than that, try not to go gonzo with the Jeep, although that may limit your fun.

Changing Swap
Do you have any back issues with articles concerning generator-to-alternator swaps? I have a '55 M38A1 Jeep and want to convert to a regular alternator. I know that Jeeps with the same four-cylinder engine I have use alternators in later years-so it should be easy, right?
Name withheld,
via e-mail

We've never done a story on that swap, but we might do an overview of the problems involved and how to overcome them. Many factors affect the swapping of an alternator into a generator-equipped vehicle, and yes, some of them are easy to remedy. If your Jeep is still stock, you have even more problems since it was originally equipped with a waterproof 24-volt generator and regulator that were hooked together by big, waterproof military cables. We're not aware of anyone who makes a kit to retrofit an internally regulated alternator in 24-volt, but conversions to a regular 12-volt system have been performed many times.

The basic swap is to use all civilian parts, including the starter, generator, regulator, distributor, gauges, switches, lights, and wiring. It's a big job and not cheap. On the other hand, the 24-volt system is fine if it all works, but replacement parts can be expensive. If you already have a 12-volt system, replacing the generator is fairly simple. Use a GM alternator with an internal regulator and a one-wire hookup, and build some brackets to mount the alternator. The pulley on the alternator needs to match the belt or belts you currently have, and the single wire goes straight to the battery. This is the simple way to convert, but a properly operating generator is perfectly good for your Jeep.

2.8L Power Trip
I own an '86 Jeep Cherokee with a 2.8L V-6. It runs well, but it's getting high on miles. I'd like to go to a more powerful engine. What do you recommend and where can I find the swap kits I'll need?
Shane Coleman
Ruston, LA

The GM-built 2.8L V-6 is notorious for being a weak dog. It was used in '82-'85 S-series trucks and in many Jeep Cherokees through 1986. Aftermarket companies do offer performance manifolds and cams, but it still won't be a powerhouse. That's why GM Performance Parts has released a new 3.4L engine assembly that's nearly a bolt-in replacement for the 2.8. It's even smog-legal for S-10s and Blazers that were originally equipped with a 2.8. The new 3.4 makes 40 more hp than a stock 2.8, thanks to a 20 percent increase in displacement and a revised camshaft. It's power numbers are 160 hp at 5,000 rpm and 194 lb-ft of torque at 2,700 rpm. It runs on unleaded regular fuel.

The GM Performance 3.4 uses the same intake manifold, ignition system, emissions system, and water pump from the old 2.8. In some cases, the oil pan and front cover may also need to be swapped from the old engine. Of course, all this info is provided with GM-built trucks in mind, but we can't see why the new 3.4L couldn't be easily swapped into your Jeep. But technically, it wouldn't be smog-legal.

You can order a new 3.4 (PN 12363230) from any GM Performance dealer.

V-8 Swap Tip
You've mentioned that CJs with the GM-built 2.5L Iron Duke four-cylinder have the same bellhousing bolt pattern as the small-block Chevy and this makes engine swaps easy. Here's some added info for you:

I don't know about the Chrysler automatic trans used with the Iron Duke, but the manual-trans versions used a bellhousing that works with a 153-tooth flywheel. That means if you're going to install an '85-or-newer GM 4.3L V-6 or small-block V-8, it will need an externally balanced 153-tooth flywheel. This was used only on '86 Camaros and Firebirds with a high-output 305 and a manual trans; '87-'92 Camaros and Firebirds with a multipoint fuel-injected 305 and a manual trans; and '86-'88 Corvettes with a manual trans. So it's a little hard to find.

Once you have the correct flywheel, use a Borg-Warner pressure plate (PN CL 155472) and clutch disc (PN CL 3741181), so all other OE parts will work.

Those are the only problems I had when swapping a 4.3L V-6 into my Jeep that had a GM 2.5L four-banger and an SR4 trans.
Kenny Gowen
via e-mail

Thanks for the added info! There's nothing better than hands-on advice from someone who has suffered through a swap.

Transmission Trouble
I have a '67 CJ-5 with the Buick 225 Dauntless V-6 and a three-speed. Except for the transmission, the drivetrain is in good shape, and the body is fairly good too. Do you have any information on bolting in another transmission, and is this Jeep worth restoring?
Daniel Gish
Louisville, KY

Any Jeep is worth restoring; the question is how much time and money will it take to do it right, and what will the Jeep be worth when it's done? A true restoration means making every part as good as it was when it left the factory, and correct, right down to the decals on the air cleaner and the factory-supplied tires. Since most of us use our Jeeps, the term refurbish is more apt than restoration. For instance, we doubt you're going to fix up the body to the point where you'll be afraid to get it scratched on some bushes-especially if it's only in fair shape to begin with.

As to the transmission, the factory three-speed for that year is a Borg-Warner T86. Though it's sufficiently sturdy for normal uses, the T86 has a poor record when used with larger tires or when abused by excessive power or speed-shifting. The earlier T90 three-speed transmission used in Jeeps is actually stronger and can be swapped in, but it isn't a bolt-in deal anymore than anything else is. The easiest way to upgrade your present transmission is to use T90 gears in the T86 case, which should only be performed by an experienced mechanic who knows how to mix the two transmissions.

Another heavy-duty option is to swap in a truck-type four-speed with the granny low First gear, such as the Chevy SM420 or SM465. Those super-strong transmissions adapt to V-6 bellhousing relatively easy, but will need an adapter from Advance Adapters (Dept. Jp, 4320 Aerotech Center Way, Paso Robles, CA 93446, 800/350-2223) to mate to your transfer case. You'll also have to make changes to the driveshaft and relocate the crossmember as well as the floorpan and shifter.

The best bet is to fix what you've got, unless more power or big tires are in your future. While not cheap to fix, the T86 should be an adequate tranny for most off-road trips as long as you don't lead-foot the gas or pop the clutch pedal.

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