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Answers to all your Jeep questions

Posted in How To: Tech Qa on May 3, 2017
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Steering Easy

What can I do to decrease the steering effort in my ’79 CJ-5? It is only driven on city streets. It has an AGR steering gear box, stock power steering pump with a press-fit pulley, and a Borgeson steering shaft. The tie rod ends and ball joints are in good condition and the Jeep runs on stock sized tires. Can I modify the pump for higher pressure, is there a pump available with higher pressure that I can simply bolt in, or must I replace the steering gear box again? Any part numbers and vendors would be greatly appreciated.

Bill Evans
Denver, CO

The power steering systems on most Jeeps are usually adequate for running stock sized tires. If your power steering feels weak, there may be something wrong or worn out. Among other things, a slipping belt can cause the system to require increased steering effort. It won’t always result in the tell-tale squealing usually associated with a slipping belt. Check the belt tension and inspect it for signs of glazing.

Aftermarket steering boxes from companies like AGR (steerco.com) can typically be ordered with a standard 12:1 ratio or a variable 13:1-16:1 ratio which provides improved steering control and requires slightly less input, especially during sharper turns. The performance of your steering box will be dependent on which one you ordered. Most fast-ratio boxes with 2.5-3 turns lock-to-lock will require more steering effort than a slower ratio steering box with 4 turns lock-to-lock.

Assuming you simply ordered a factory replacement style steering box, there may be other elements causing your Jeep to require increased steering effort. If the box had been broken or severely worn, it’s possible that the power steering fluid became contaminated with metal bits. These metal bits in the fluid can damage the pump, which would reduce pump volume and pressure. I’ve also seen improper steering system bleeding prior to firing the engine cause power steering pump failure. A worn or damaged power steering pump could be causing the problems you are having. You might want to change the pump if it’s a high-mileage unit. Don’t forget to thoroughly flush out the old fluid and properly bleed the system prior to startup.

A ram-assist is generally not necessary for tires that are 35 inches in diameter or smaller, so I don’t think something like that would be needed on a Jeep like yours. However, if the power steering belt is tight and in good condition and your power steering pump is still functioning properly, you may consider installing a steering box with a lower gear ratio. The steering box from an FSJ application of the same era of your Jeep will provide 3.5-4 turns lock-to-lock. Of course, you will be juggling the steering wheel more during sharp turns and on tight trails, but you’ll likely be able to turn the steering wheel with one finger, even when parked.

Anemic Auto Transmission

I love the magazine. I finally broke down at Christmas and got a subscription. I was tired of sorting through the rack at the local store, only to find they were all gone. I read the magazine cover-to-cover, then donate it to the local Veteran’s Community Living Center. I have a ’04 Jeep TJ with the ever so problematic and anemic 42RLE automatic transmission. As I’m heading down the road, it either shifts into overdrive way to early and the engine lugs down until I manually shift it out of Overdrive or it hunts in and out of Overdrive, downshifting/upshifting. Most of the time I have to drive it out of Overdrive and that makes the engine spin at 3,500 rpm, which is not good for a constant speed or long distance. I usually have to drive slower than the posted speed limit, letting other cars pass me. In four-wheel low range and off-road there are no problems with it, just getting up to highway speeds is the issue. I have taken it to Jeep several times and have had the transmission reflashed and the oil and filter changed, but it still doesn’t solve the problem. Is there an upgrade kit/shift kit or a direct replacement of the 42RLE transmission that will solve the problems, or am I looking at a Jeep upgrade in the future? What have other readers done to solve this problem? It is all stock with the 4.0L engine and some minor upgrades (winch/bumpers/tow package-for behind my motorhome). It has 63,000 miles on it. The tires are stock size so I don’t think it’s a tire/drivetrain problem. Any help will be appreciated, I’m too young to grow bald pulling my hair out!

David Rogers
Walsenburg, CO

Many were thrilled when the Jeep Wrangler finally received a four-speed overdrive automatic transmission for the ’03 model year. However, the lackluster performance of the 42RLE was less than ideal, even more so for those who installed larger tires behind stock axle gears. Part of the problem stems from the transmission gear ratios of 2.80 (First), 1.55 (Second), 1.00 (Third), and 0.69 (Overdrive). These transmission ratios cannot be changed, although you could overgear the axles to compensate for the poor performance. The other problem stems from a somewhat tight torque converter, which was most certainly added to help increase the fuel economy of the aging 4.0L inline-six. You might consider switching to a slightly looser torque converter to help liven up your Jeep. Companies such as TCI (tciauto.com) and ATS (atsdiesel.com) offer performance replacement torque converters as well as complete replacement performance transmissions for the 42RLE.

Keep in mind that these performance transmissions and torque converters can create more heat than the factory components. You should back them up with the largest add-on auxiliary transmission cooler you can fit. Companies like Flex-a-lite (flex-a-lite.com) offer add-on transmission coolers with brackets that are designed to simply bolt-up to the Jeep Wrangler.

Trail Holdup

I'm installing 265/75R16 (31.6-inch) BFG KO2 tires on my stock-ish ’11 two-door JK later this week. My current tires are 33.1 inches. I'm going down in diameter by about 1 1/2 inches. In turn, the ground clearance below the diffs will decrease about 3/4-inch (from 9 3/4 inches to 9 inches). By doing so, will I not be able to keep up with other drivers on trail runs if everyone else is running 35-inch tires? I don't want to take the fun out of a day for others having to wait up for me to navigate over obstacles. Is there a general rule of thumb or good practice used when organizing group trail runs? Is it best to divide the groups by tire diameter? Can an experienced and knowledgeable driver running 31.6-inch tires handle anything that a JK driver with 35-inch tires can, without destroying the undercarriage in the process?

Mark E. Geres
Via facebook.com/jpmag

It’s not uncommon for Jeep owners to think they can’t conquer a trail because everyone else on the trip is running a larger tire size. More often than not, I see people run much larger tires than they really need for the trails they plan to encounter. This can often cause all sorts of unforeseen issues such as axle failures, steering failures, driveshaft failures, and so on. In most cases, the guy that breaks his Jeep is the one that holds up and burdens the rest of the pack. Regardless of what tire size you run, you should travel off-road with a like-minded group of off-roaders. If their idea of a good time is to find the most extreme route and blast through as fast as possible, they are probably not a good fit for a Jeep built like yours. On the other hand, there have been many times that I have seen seasoned drivers in stock Jeeps run circles around new drivers in heavily modified rigs with much larger tires. Without personally knowing the group that you travel with, the trails they frequent, or your driving skill level, it’s hard to make a call like that. The only way to know for sure is to give it a shot and hang at the back of the pack. That way you can park and hike up part of the trail to see if it gets rougher than you prefer. If it does, you can simply hike back out and easily turn around.

I’ve often found that if you come prepared in other ways, you can offset the larger tire size advantage of other Jeeps. Proper recovery points, sturdy skidplates, heavy-duty rocker guards, and a recovery winch can trump larger diameter tires in many cases. A properly built and well-outfitted Jeep will make it further up the trail than a poorly thought out Jeep on large diameter tires.

2.5L to 4.0L Swap

I have a ’02 TJ Wrangler with a 2.5L four-cylinder. There is a ’96 4.0L engine, AX-15 manual transmission, and transfer case with all the wiring for sale locally for about $900. Would it be worth swapping the 4.0L into my Jeep or would it be better just to buy a 4.0L TJ? I work in a fabrication shop so I could do some fabrication if I needed to. It has quite a few miles on it so I was thinking of doing a stroker kit. Which brand would you recommend?

Morgan Isaac
Via email

Unfortunately, the 2.5L to 4.0L engine swap has never been a very cost-effective conversion. It’s usually much cheaper and a lot easier to simply sell the 2.5L Jeep and purchase the 4.0L TJ you want, unless you have a lot of irreversible modifications done to your Jeep, such as an expensive paint job or fabricated suspension.

When you consider the bigger picture, you realize that the engine, transmission, transfer case, and wiring are usually the least expensive part of the conversion. You’ll likely spend thousands more on the exhaust, driveshafts, cooling, motor mounts, and more. Even the cheapest of engine swaps that seem elementary will cost around $5,000 once all the bugs are worked out. If you put that $5,000 in along with the selling price of your 2.5L Jeep, you’d likely end up with a pretty nice 4.0L TJ, right?

Now, if you decide to purchase the used drivetrain and make the swap, there are many companies that offer stroker rebuild kits for the 4.0L. If the engine you are considering is completely worn out, you might opt for a Golen (golenengineservice.com) 4.6L long-block stroker engine. The Golen 4.6L is available as a bolt-in long-block for up to ’99 model years as well as for the ’00-’06 model years. It’s said to produce 270 hp and runs on 91-octane pump gas.

Because I Have It!

I have a few questions on an experiment I may take on this spring. I recently picked up a ’98 two-door Cherokee for $775 with 166,000 miles on the clock. It has a 4.0L with the automatic transmission. As you might have guessed, there were some issues. Most are common Jeep things such as ball joints, a U-joint, coolant leak, and so on. One of the most noticeable issues is that the transmission isn't quite the healthiest anymore, especially since it was 2 1/2 quarts low on ATF when I got it. I just so happen to have a brand new TorqueFlite 727 in my garage. It was leftover from my father’s TJ project years ago. Have you ever done a 727 to 4.0L conversion? I've read a few threads on the subject but have not seen any real answers to possible swap issues such as the flexplate, starter, and other issues. Any information would be helpful! I’m still trying to decide whether or not to go with an AX-15 swap instead of sticking with the automatic.

Alex Lee
Via facebook.com/jpmag

My first question would be why make a swap like this? You would be giving up the overdrive in the AW4. Generally, swaps that begin with “because I already have a…” rarely ever make sense. Realistically, you’ll likely have more money wrapped up in a an aftermarket crank trigger sensor, driveshaft modifications, a new shifter, torque converter, and so on than you would have to spend to properly repair the AW4 already in your Jeep. The AW4 is actually a great transmission that is revered for its performance, durability, and longevity. It’s not unusual to see an AW4 last more than 250,000 miles when well maintained. Furthermore, a good used AW4 would only set you back around $300-$400, and it would simply bolt into your Cherokee without issue. Ultimately, I wouldn’t recommend a swap like this unless you were simply looking to spend more money to say you have something original, even if it is less desirable.

Spicer 18 Weeping

My Spicer 18 transfer case is leaking from the front and rear outputs. Should I replace the seals? If so, is this straight forward or is there some special procedure?

Name Not Included
Via email

It’s not at all uncommon to find a leaky Spicer 18 in an older Jeep. It’s not that the Spicer 18 is a problematic transfer case—it’s just old and has many areas where oil leaks could surface. First, you’ll want to make sure the leak is indeed coming from the yoke or yokes. You can wipe down the area with brake cleaner and let the Jeep sit. A slow leak will form a drip and you’ll be able to more easily see where the drip is coming from after wiping the area clean. Once you have found that it is indeed coming from the yokes, remove the driveshafts and use an impact wrench or breaker bar to remove the yoke nuts. The yokes should slip off easily, but you may need a puller if they have been in place for decades. A seal puller is helpful when removing the Spicer 18 yoke seals. They are pretty far down in the output castings. Companies such as Harbor Freight (harborfreight.com) offer a twin-tip seal puller that can simplify the task, but you can also get in there with a blade screwdriver and hammer to pry out the seals. A new seal can be tapped into place using a short length of tubing and a hammer. Check the yokes for wear and replace them or sleeve them if there is a deep groove worn into the sealing surface. Omix-ADA (omix-ada.com) offers Spicer 18 replacement yokes if yours are worn out.

Clean the splines on the output shafts and yokes and smear a bit of silicone on them to help with sealing. Some Spicer 18 output nuts have provisions for cotter pins, but you should also use thread-locking compound too. Torque the yoke nuts to 100-120 lb-ft and reinstall the driveshafts. Don’t forget to check the transfer-case fluid and refill as needed.

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