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April 2012 Your Jeep Tech Questions

Posted in How To on April 1, 2012
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Confessions: Jeep Hoarding
Cappa, we love hoarders like you. You make parts available to people like me. Looking at your axles in the Aug. ’11 issue in your back yard, how does one know when an axlehousing is too rusty to do its job, either as part of a collection or on a vehicle?
Jim Leister
Via email

Jim, John may be a hoarder, but I personally have benefited more than once from his psychosis (and share them). I got a free offset Dana 44 from him that resides under my current flattie.

Well hmmm...in my experience an axlehousing is gonna have to be pretty darn rusty to be deemed useless in a vehicle. Growing up on the east coast and spending a few years in the snow-bound state of Ohio where the roads are heavily salted in the winter, I have some experience with this. I rebuilt a Dana 44 out of an ’80 FSJ in Ohio. This axle was buried in the dirt under an old Grand Wagoneer for what must have been at least 10 years. The caliper mounting bracket dust shields just crumbled into dust when touched, but with some elbow grease, a wire wheel, and some paint I was able to reuse the structural part of these brackets (minus the dust-shields). And even though they were very pitted, they worked fine. The knuckles, hubs, and housing were also in pretty darn good shape after cleaning them up. The 90W gear oil kept the inside of the diff looking factory-fresh. With new ball joints, bearings, seals, and other wear parts, this axle was in great shape.

I also snagged a rear Dana 44 from a ’96 Honda Passport. This SUV was so rusty that I could literally push my finger through the frame, but the axle was in great shape. I didn’t even swap out the wheel bearings and most of the factory paint was still on the axle. Hell, I ran the junkyard rotors and pads on that axle for a while! Now if the inside of the carrier or ring-and-pinion are rusty, that’s a different story. In that case you will need to replace the bearings and seals and clean the heck out of the inside. It’s gonna be a judgment call on whether or not to replace the ring-and-pinion as well if they are pitted at all.

Long-Haul TJ
I have a ’00 TJ with the 4.0L and an automatic behind it (it was a cheap deal with the automatic). It has a cold air intake, 31-inch tires, and solid front and rear bumpers. I use this Jeep to go camping constantly and travel long distance to get there. My longest trip was to Northern Quebec, Canada, where I stayed for two weeks. The bush road getting back to the site is forty miles of washboard dirt roads.

I was thinking of swapping a 5.3L Chevy V-8 with an automatic to help with the long-distance travel. I found a website explaining why a Chevy swap should be suggested, and what adapters to use. Is this a wise swap? I do haul a trailer with an ATV, plus 350lbs of gear, parts and fuel. The other option is just buying a larger vehicle, but the Jeep is to squeeze through tight trails.

I do not wish to raise the Jeep any higher then it sits now in its stock form. Is there a suspension system that you recommend to keep the Jeep around stock height, but is reliable? If I decide to go through with the swap I would swap in the Dana 44 rear axle for strength with disc brakes. The stock transfer case I will reuse, but will it hold the load of the Chevy along with the trailer and gear? Thank you for your input and good mag, keep it up. 
Jason Prince
Beaver Falls, PA

Cool deal on a TJ, and finally an expedition rig we can relate to! Many people have swapped in a 5.3L Chevy V-8 and 4L60E combo in a TJ, and it can be a good engine for some Jeeps. However, there are complications that make it a less-than-ideal swap for others. I would advise against it for what you are doing for a couple of reasons. First, I am willing to bet that you have planned the engine swap because the 4.0L in your TJ is feeling weak while towing and driving down those back roads. That’s a common problem for any TJ with larger-than-stock tires, and can most likely be best remedied with a gear swap. Jp’s project TJ with a 4.0L, stock 3.73 gears, 32-inch tires, and an Avenger Supercharger (making roughly 100hp more than stock and 55-percent more torque) could hardly pull grades like a stock 4.0L TJ prior to re-gearing the axles. The fact is that lower axle gears will bring back the performance of your TJ at a fraction of the cost of the drivetrain swap and will retain the factory reliability you are gonna need when you are miles and miles away from any garage.

To decide on a new ratio use the following formula: new tire size in inches/old tire size in inches x old axle ratio = new axle ratio. Assuming your Jeep has 3.07:1 gears with its three-speed automatic transmission and had 27-inch tires from the factory, you would plug in 31 / 27 x 3.07= 3.525. However, we’d up that to at least 3.73:1s and possibly 4.10:1s for your TJ.

Second, converting a newer Chrysler product to any GM engine is gonna require a major re-wiring of most of the electrical system. Everything ranging from the Chrysler computer to the Jeep’s gauges won’t “speaky the same language” as a 5.3L GM engine and tranny. You will also have to build or buy a conversion radiator, exhaust, fuel pump, driveshafts, crossmembers, shifters, etc. If you insist on a V-8 swap, I would recommend doing a Chrysler-based swap (5.2L, or 5.9L from a Grand Cherokee or Dodge) because while you will still need to redo much of the wiring and get a new computer, many of the ancillary parts your Jeep already has can “speak” to other Chrysler parts thus making the swap much more straightforward and in the end more reliable.

As for a relatively low lift, check out the 3-Day TJ for $3K build in this issue for info on a TJ budget boost. I would also consider a 2-inch Old Man Emu suspension with shocks to optimize your ride on long wasboard roads. After all, that’s what most of the long outback roads in OMEs home of Australia are like!

XJ8 60
I have seen that Mopar is selling the J8 Dana 60 rear axle. It looks like a nice little Dana 60 with spring perches. I know that this rear axle is wider than an XJ axle, but how hard would it be to put JK axles under an XJ? I guess I’d go with a JK Dana 44 front and the J8 Dana 60 rear.
97xjproject
Via jpmagazine.com

I found a website that says the Mopar Dana 60 has a track width of 61.9 inches. But that’s track width, not distance between the wheel mount surfaces. In reality, the JK axles are roughly 4-5 inches wider than XJ/YJ/TJ axles. It may seem like a lot, but if you’re adding larger tires on an aggressive build, the extra width will come in handy.

If you do go to a Dana 44 front, however, you’re probably looking at a custom axle assembly because the Mopar J8 Dana 60 has a 5x5.5 bolt pattern. The JK axles have a 5x5 pattern that’s not cheaply converted.

If you decide to ditch the J8 axle idea, you could look for a pair of take-out JK Dana 44s. The rear JK Dana 44 is burly strong in a 5,000lb or lighter Jeep. For the rear you’d need to cut off all the JK brackets and weld on some spring perches. Child’s play! Up front, apparently, the control arm mounts on a JK front axle will work for an XJ, but you will have to move or fabricate the spring and shock mounts and do something about the track bar and drag link. You can use a factory JK tie rod. You may need to shorten the driveshafts too and you will need some wheels that match the 5 on 5 bolt pattern of the JK axles.

Trackless YJ
I am trying to get my ’89 YJ to flex a little more. Right now it has 5-inch-lift springs. I have already removed a leaf from the spring pack. It helped a lot but it’s still not up to par. Reading the article “Jenny Craig Jeep” (Oct. ‘11), you suggest that the track bars be removed. Besides the weight savings aspects, would it give you more articulation? What defines a properly set up leaf-spring suspension?
Brad Vest
Via email

Yep, ditch the track bars. I am not sure there is a fit all “definition” of a properly set up leaf spring suspension, but track bars on a YJ are somewhat redundant. They supposedly lower the roll center of the vehicle. I guess that means they would make the Jeep less likely to roll over during extreme cornering. I would also make sure your shocks and or shackles are not limiting your flex and run sway bar disconnects. Often with longer, highly arched leaf springs you also need longer shackles to allow the springs to flatten under compression (they get longer than a stock spring). I’d be careful with removing leaves from the pack. This may make the suspension more flexible, but could also strain the springs too much causing flattening or allowing the spring to bend. Or worse, a leaf could break. If a spring fails on the trail it could ruin your day, trust me! Also, in my experience most aftermarket lift leaf springs need to settle a little with use. The more you use them, the more they’ll flex…assuming one of the above components is not limiting their travel.

Proper bumpstop height can also help your springs work correctly and prevent spring damage. You can test-cycle your suspension by putting your Jeep up on jackstands, removing the wheels, and disassembling your spring packs. Then loosely reattach your axles to the main leaf only. While the Jeep is supported by the jackstands, use a floor jack to cycle the suspension to check that the shackles are long enough and that the bumpstops are doing their job.

Write Us!
Got a tech question you’re just itching to get answered? Send it on in to Jp magazine, Your Jeep, 831 S. Douglas St., El Segundo, CA 90245, or e-mail it to jpeditor@sorc.com.

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