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Your Jeep Tech Questions Answered

Posted in How To: Tech Qa on October 9, 2019
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Resto vs. Restomod and ABS
I have a 1970 Jeepster Commando with a 225 V-6 and a Turbo 400 transmission, which I am planning to restore and update all at the same time. My plan is to purchase a 2001 or 2002 V-6 Camaro with a 4L60E automatic and rebuild the motor and tranny and move them to the Jeep to get an even-firing fuel-injected V-6 with an overdrive automatic. Novak makes the adapter for the transfer case and with the engine having all the same basic dimensions it should be a relatively easy swap. The differentials will be 3.73s and Torsen-style limited slip in the rear. I plan to change the brakes and put four-wheel disc brakes on it, and I wanted to know if anyone has tried or considered putting an ABS on an older Jeep? I was thinking the ABS on the donor Camaro should work by relocating the tone generator on the transmission tailpiece to the transfer case output. By feeding this to the Dakota Digital instrument cluster and the ABS the rear wheels would be taken care of, but how do I get front disc with tone generators? Is there a kit out there for the front that would have the tone generators? Do the tone generators all have to match in frequency, as in the front generating the same tone as the rear? I was also considering cutting down the GM 10-bolt rear end out of the Camaro and putting a hub kit on it to end up with a full-floating rear axle and a stronger rear end than the Dana 44 with two-piece axles (which I broke twice in a previous Jeepster with the standard V-6). I plan on using 16x7-inch wheels and 265/75R16 tires. This project is in the planning stages so I still have options so your ideas are appreciated.
Name withheld
Via email

Wow, there are lots of things to address here, so let's start with your beginning comment about restoration. While you may be planning on restoring the body, you most definitely aren't restoring the Jeepster. Restoring, by definition, is returning it back to its factory condition when it rolled off the assembly line. What you're planning on doing is really more of a restomod, which there is nothing wrong with doing, but it deserves clarification. It also is worth mentioning that as Jeepsters go, yours is one of the more desirable versions with an odd-fire 225 Buick and TH400 from the factory (assuming it's factory). That's a pretty cool combination, and both the engine and tranny are very well supported should you want to truly keep the vehicle original, which we would urge you to do. That odd-fire engine is a classic and can easily keep up with modern highway speeds in proper tune, and things like aftermarket fuel injection can make it drive nearly identical to the later-model drivetrain without all of the extra work and hassle of a drivetrain swap. Plus, most gearheads and all Jeep purists would award more style points for working with what you have (which has a ton of potential). You'd also end up with a lot less money in the project overall.

If you're dead set on a later-model drivetrain, or the original stuff is DOA, then your 4.3L V-6/4L60E combo is a viable one. Keep in mind that it doesn't have to come out of a Camaro. Many S-10 and 1/2-ton GM trucks are equally viable donor candidates, and you can choose anything from TBI to Vortec to modern direct-injected versions, depending on how complex you want to make things. If you want to keep things simple and economical, then it would be hard to go wrong with TBI, which was used from 1987-1995 in most models, and longer in some of them. Later Vortec versions are equally well supported and only slightly more complex. It bears mentioning that all of the hassle and work put into swinging a GM V-6 under the hood is also nearly identical to a V-8, and there's ample room under a Jeepster hood for a V-8. We speak from personal experience when we say that a drivetrain swap is exactly the same amount of work, whether you're doing a V-6 or a V-8, and if the underhood space affords it (which it does in your case), we'd opt for the V-8 every time. You get a lot more power for the same amount of work, and the adapters required are identical.

As for adapting antilock brakes, you're asking for trouble. In short, there's just not an easy way to do it, and in the end, you may end up with worse brakes than if you stuck with conventional methods. You are correct that ABS (antilock braking system) units work off of pulses or tones generated by at least the front wheels and the rear axle, or all four wheels. The problem you will find is that the systems are vehicle-specific, meaning that the ABS designed for a Camaro will be very different than one for an S-10, an Explorer, or a Ram 1500. It seems simple on paper to just make an ABS from one vehicle work on another, especially if all of the components come from the same place, but that is far from the case. Even if you could figure out how to mount all of the tone rings from the same factory ABS and get them to work on a different vehicle (which would be difficult), the valving of the module itself and the programming required would be completely wrong for anything other than the vehicle for which it was originally intended. So, even if you managed to get it swapped and all hooked up just like it was on the car it was originally designed for, you'd most likely have a very poorly performing ABS.

A better track on the braking end of things is to focus on how to make the brakes work well with your project. Good brakes are key to any successful vehicle build, and we applaud you placing a priority on them. But we also have to ask: Why do you want antilock brakes? Do you feel you need an ABS, or do you feel there will be people driving the vehicle that need it? As enthusiasts, most of us understand the theories behind an ABS and can apply the same principles to greater effect without it. There have been multiple times when an ABS has actually put us in more danger on a trail because the system thought it "knew better" than the experienced driver behind the wheel. Due to the complexity of adapting an ABS and its generally poor performance off the pavement, we wouldn't recommend messing with it. Instead, focus on making the brakes work as well as possible on your Jeepster. There are disc brake kits available for both of the factory axles under your vehicle as well as just about any aftermarket or swapped axle you can think of. Front disc brakes in particular will vastly improve your Jeepster's braking performance.

As for your 10-bolt idea, again, it looks good on paper, but the problem there is no full-float axle kit available for a 10-bolt, so you're talking about custom machining, axleshafts, and more. A GM 10-bolt and a Dana 44 both have a ring gear diameter of 8.5 inches, making them roughly the same strength-wise. The main disadvantage with the 10-bolt is the C-clip rear axles, which allow a tire to be separated from the vehicle should an axleshaft break. The Dana 44 under the Jeepster can be upgraded with one-piece axles or even converted to a full-floater, which is a whole lot cheaper and easier than building the highly custom 10-bolt you're talking about.

Cluster of a Cluster
I have a 2006 TJ 6-cylinder automatic. The analog gauges have stopped working. I have replaced the PCM (twice), alternator, starter, battery, cables, and all fuses. I even replaced the cluster. They still don't work. I can't find anybody who can help.
Robert T.
Via email

We've dealt with similar situations off and on with a couple of different TJs, but nothing on a 2006 TJ. While '97-'06 TJs are "all the same," there are actually quite a few variations in terms of electronics that are worth noting. Therefore, in addition to our own experience we also bounced your question over to Chris Durham at Chris Durham Motorsports (cdmracing.com). Below is a combination of his advice and our own.

Most likely you are chasing a wiring issue and not a component issue. All of the gauge cluster's information is transmitted over a CAN-bus system. Though common and fairly complicated on later systems like the JK, the CAN-bus on a TJ is an early version and comparatively simple. Though this is a watered-down explanation, CAN-bus on a TJ is like a primitive version of the Internet where various vehicle systems communicate with one another via a common pair of twisted wires that run throughout the vehicle. Instead of power and ground, this twisted pair of wires sends messages back and forth between various vehicle components on the Net via black magic and wizardry. When it works, just like your laptop talks to Google, it all just seems to work out. Your problem is most likely somewhere in the twisted pair of wires, or it's a bad connection somewhere in the wiring harness. The Can-bus system daisy-chains between the cluster, the PCM, the ABS controller, the body controller, the instrument cluster, the airbag module, and a few more items. Any break in the chain can cause problems, but to add to the confusion, the connections aren't always in series but are sometimes parallel. In other words, A and B might be connected in a series to C, but C and D and E all have redundant connections. If there's a wire break between A and B there will be a problem, but a break between C and E or D and C may not manifest itself as a problem all of the time because there isn't a break on the Net as a whole. To make matters worse, because everything is interconnected, the bad component can be hard to pin down. Durham mentioned one extreme case where a bad crank sensor was shorting the 5V signal needed to make everything else in the chain work. Because of that short, nothing worked. It wasn't until that bad sensor was unplugged that everything else started responding. If that sounds annoying, it's because it is annoying.

Back to your specific problem: First off, we would make sure the ECMs you've swapped are all 2006 models. In our experience as well as CDM Racing's, 2003-2006 computers are all year-specific; you mix and match at your own peril. The clusters are less problematic, but it is worth noting that the 2007-and-later JKs are a nightmare in terms of clusters, TIPMs, body controllers, and much more. If possible, go back to your original ECM, or at the very least, ensure that your ECM is for a 2006 model. From there, we would ohm out the wiring between the ECM and the cluster and make sure there is continuity among the twisted pair of CAN-bus wires. You'll need a factory service manual to identify those exact pins, but continuity tells all. Durham mentioned that you should be able to ohm out continuity between the OBD-II port and the ECM to rule out conflicts with the ECM wiring, and he says that there have been situations where the pins at the back of the cluster get pinched and break without appearing to be compromised. Because you've eliminated all of the other possible suspects, the only thing left is the wiring. While the most elegant solution involves finding the problem site in the harness and fixing it, few people would fault you for running a new twisted pair of wires between the cluster and the ECM if you can't find the break.

Squeaky Brakes
I bought a 2011 Wrangler a couple years ago with 77,000 miles. The brakes squealed occasionally so I put new middle-of-the-road pads on. This fixed the noise for a while but it has returned. It actually chirps like a bird until I apply enough peddle pressure. I then had all four rotors turned with the same result. I then took it to a repair shop and they said it needed ceramic pads. They installed them but I ended up with the same result. Most recently I put new calipers on the passenger side where the noise seems to come from. Same result. I am currently about $750 in trying to stop the chirping but no better off than when I started. I've read it could be a bent axle and several other things. Is this a common problem with this model or can you possibly point me in the right direction? I've had a few Jeeps over the years, and I drove a '57 Willys in high school. I love them but this one is about to drive me nuts. Any advice would be appreciated.
Jay Hazen
Via email

This is another one of those problems that's difficult to diagnose without actually working on the Jeep. Most of the time, squeaky brakes are the result of worn or warped brake components. Some of the time, squeaky brakes are caused by foreign matter (rocks, mud, etc.) getting into places it's not supposed to be. Rarely, squeaky brakes are caused by something further upstream in the system from the calipers, pads, and rotors. It sounds like you've replaced the most likely culprits, so we'd look upstream.

You've already tried a couple of different sets of pads and replaced the rotors, which is where we would have started. Surely with all of the brake work that has been done, someone at some point would have knocked the tiny rock or bits of gravel out of the brakes and killed the squeak if that was the cause. Still, it might be worth double-checking, as just a few pebbles wedged between a dust cover and a knuckle (where most people wouldn't bother to look) can cause the symptoms you describe. A bent axle is theoretically possible, but unless you've been four-wheeling your Jeep really hard, have jumped it a few times, or it has been in a wreck, a bent axle is highly unlikely.

You mentioned in your letter that you are in central Florida, and having been to the area, we know that the most popular form of off-road recreation is mudding. Even if you yourself aren't into mud, the previous owner may have been, and we know firsthand that the sandy mud down there can be particularly rough on brakes, bearings, seals, and other rotating components. If you've thoroughly inspected and replaced the most likely culprits in the brake system, we'd start looking at nearby rotating components. Though we've never been able to really explain it, we have had situations where debris in the axleshafts and even steering components caused the squeaks you describe—a squeak that persists until brakes are applied. The drag introduced when the brakes are applied can center up slightly worn components at times and kill a squeak momentarily. In addition to an abundance of water down there, it's also pretty humid, so it's easy for the brake fluid to be contaminated by moisture. Flushing the brake system wouldn't be a bad idea. Last but certainly not least, you might try replacing the master cylinder. We've seen situations where a master cylinder doesn't release all the way and leaves a small amount of pressure in a brake circuit, which can cause the pads on one or more brakes to drag just enough to cause a squeak.

No Clutch
I have an '82 Jeep J10 truck that is having clutch problems. I have installed a new clutch and can push the pedal to the floor with my finger. It has been adjusted out as far as it will go. Still no clutch. What is wrong?
Dave T.
Via email

From the sounds of it, the linkage isn't releasing the clutch at all. The first thing we'd do is inspect the clutch linkage and make sure everything was reassembled correctly and is working the way it's supposed to be. Because it's a mechanical system as opposed to hydraulic, any problems should be pretty apparent with a thorough inspection. Have an assistant actuate the pedal while you watch the linkage at the clutch fork.

If the external linkage checks out, then the problem must be internal, and you'll need to pull the transmission back out. Did the clutch fork pop off the pivot ball? Did you reuse the original clutch fork or get a new one? If you used a new one, compare it to the original and make sure they're the same. Same thing goes for the throwout bearing: Compare the distance between the face of the bearing (where it engages the clutch fingers) and the contact point for the clutch fork between the new and the old bearings. This distance (or "thickness") of the throwout bearing is critical, and unfortunately it would be pretty easy to install the incorrect one. Lastly, though it's unlikely since it sounds like everything bolted up just fine, we'd check the part number for the clutch and pressure plate to make sure you got the right clutch for your application.

 

Max Tow Traction
I bought a 2020 Jeep Gladiator Sport S model with the Max tow package and a 4.10 axle ratio. It came in with open differentials, even though I had specified rear traction control to the dealer. So, I figured I'd just get E-lockers for it. Auburn Gear has no listing for their Ected. Eaton has no listing either. I checked with both manufacturers direct. I went to Quadratec and 4 Wheel Parts. One said to install a different complete axle and use an ARB Air Locker. The factory Rubicon has E-lockers both front and rear, but the dealer is having trouble getting any parts information. I think the Rubicon uses a different Dana 44 than the Sport with Max Tow. Could you please help me find parts and numbers to fit my Jeep?
Ray W.
Via email

Even though the Gladiator has been out for a few months, information is still a bit spotty and some of the finer nuances are "coming soon," such as the differences with the Max Tow package and the Rubicon. From what we've been able to glean, you are correct in all respects. The Max Tow package uses different rear axle components than the Rubicon, which is also different than the Sport in terms of differential crossover and availability.

To be honest, because everything is so new with the Gladiator, we are kind of in a holding pattern just like you are in terms of getting definitive information. For example, we don't know as of this writing if the Max Tow 44 doesn't come or isn't available with the Rubicon locker because it physically won't fit, or if it's just because the differential isn't rated for the capacity of the Max Tow package. We also were able to verify that there is not a part number yet for a locking differential for the Max Tow package; moreover, we weren't even able to verify that's going to be an option. The traction differential you are referring to is a limited slip, not a locker.

As difficult as it might be to accept, you might consider waiting a few months for the dust to settle. By then the aftermarket will know what physically fits and what doesn't with all of the various packages available for the Gladiator, and how those packages cross with the JL models and options. There are inevitably some doldrums between when a new model is released and when products start becoming available for it, and we are smack in the middle of it. In fact, we know of at least a dozen aftermarket companies that are busy ripping apart brand-new Gladiators as we speak, but it takes a little time before products can be developed that will work for brand-new models. While ordering a complete aftermarket axle with a locker is certainly an option, it's far from the best or least costly option. By the time you read this there should be a lot more information available and more definitive answers, with products to follow shortly thereafter.

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