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Answers to all your Jeep questions: Auto vs. Manual, New Wrangler or Not and more.

Posted in How To: Tech Qa on January 12, 2017 Comment (0)
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Auto vs. Manual

I have a ’86 CJ-7 with a Holley-injected GM 350 V-8, TH350 three-speed automatic transmission, and NP205 transfer case. The axles have 4.56:1 ratio gears and the Jeep rolls on 37-inch Goodyear MT/R tires. All of my prior Jeeps had manual transmissions. I do enjoy the automatic on steep climbs and it does make rockcrawling a little easier, but I really miss the compression braking of the manual transmission on downhills. Either way, the TH350 has to go. With the 1.96:1 low range gearing in the NP205, I have a hard time bumping over big rocks. My plan is to go with a 700R for its 20 percent lower First gear and better highway speeds. The other option is an NV4500 five-speed manual transmission from a ’80s Chevy that a friend will sell me for around $500, including the bell housing. Our Jeep club is based in Pike County, Illinois, so the trails are tight, muddy, and full of rocks with some very steep hills. The Jeep isn't all chopped up and we like to cruise in it too. Just curious about which way you would go and why. Thanks in advance!
Karl Anderson
Mendon, IL

Choosing between a manual and automatic transmission is mostly based on personal preference. However, there are some types of off-road driving that are much easier on the driver and the drivetrain components with an automatic. Manual transmissions offer a more direct drive than automatic transmissions. Manuals are more likely to shock-load other drivetrain parts. The torque converter of an automatic transmission acts as sort of a cushion that absorbs some of that harshness. I say all this because my personal choice for your vehicle might be different depending on what axles are under your Jeep. If you are running 1/2-ton axles, such a Dana 44 frontend with stock or even aftermarket chromoly ’shafts, I might be inclined to stick with an automatic to preserve it if I planned on driving aggressively. The 37-inch tires are about as big as you want to go on the 1/2-ton axles. The direct drive of a manual transmission won’t be doing the steering U-joints and axleshafts any favors.

Now, if low range gearing is one of your main selling points for performing this transmission swap, let’s look at some numbers. The 700R4 has a First gear ratio of 3.06:1 and the TH350 has a First gear of 2.52:1. While it is true that the First gear in 700R4 is about 21 percent lower than the First gear in the TH350, the calculated overall crawl ratio differences are negligible. When the transmission First gear ratio, 1.96:1 transfer case low range ratio, and 4.56:1 axle ratio are all multiplied, we come up with a 27:1 crawl ratio for the 700R4 and a 22:1 crawl ratio for the TH350. Given these numbers, I really couldn’t justify making the swap, unless, of course, highway driving at speeds more than 70 mph was extremely important to me. That’s where the 700R4 0.70:1 Overdrive gear will really shine. Realistically, I don’t think you will even notice the difference in off-road performance of a 27:1 or a 22:1 crawl ratio. In this scenario, the 700R4 would be a waste of money and effort in my opinion.

The NV4500 five-speed manual transmission was not introduced until 1992. So be careful if your buddy claims he has an ’80 NV4500. It may be some other transmission, or he may simply have the year wrong. The ’92-’94 GM NV4500 transmissions are some of the most desirable. They have a 6.34:1 First gear ratio. Later GM NV4500 transmissions received a 5.61 First gear.

You sort of have two things working against you. The 4.56 axle gears are a little high for the 37-inch tires. The other issue is the 1.96:1 low range ratio of the NP205. Each on its own isn’t a big issue, but when combined, they are hurting your overall crawl ratio. You might be better off with 4.88, 5.13, or even 5.38 axle gears if you eventually go with an overdrive transmission, regardless whether it’s an automatic or manual. Another option is to swap a JB Conversions (jbconversions.com) LoMax 3:1 gearset into the NP205.

Installation of a crawl box like the Offroad Design (offroaddesign.com) Magnum Box or Doubler Dual Transfer Case System could provide the extra low-range gearing you need. However, both of these products will knock several inches out of your rear driveshaft, which may already be pretty short with the drivetrain you’ve selected. The Magnum Box is 6.25 inches long and the Doubler will add 6 inches to your existing transmission/transfer case combo.

Ultimately, the choice is up to you. You have to live with the Jeep, not me. Given the application and your needs, I’d probably go with the NV4500 manual transmission and take it easy on the front axle if it’s a Dana 44.

New Wrangler or Not

Are you certain about any changes to the Jeep Wrangler in the near future? I’m thinking of buying one now, but if you suggest waiting, then I might wait. I probably only go off-road once a year. I’m looking at slightly used Jeep Wranglers.
James Johnson
Toronto, Canada

It’s not entirely impossible to predict what the new ’18 Jeep Wrangler JL will or won’t have. There are a lot of news reports and spy photos out there already, but what is difficult to predict is the actual performance of the vehicle. We can only speculate. Generally, Jeep has always made the next-generation Wrangler more capable and comfortable than the outgoing model. Based on swirling rumors, I suspect the ’18 JL Wrangler will be lighter than the current JK and get better fuel economy. Other rumored items of interest are an eight-speed automatic transmission, an available turbo four-cylinder, and a 3.0L diesel option. The pickup version seems a given, with the recent news and spy photos floating about. Will all of this be worth waiting for? It’s hard to say. That’s something you have to answer for yourself. One thing is for sure. If past and current Wrangler sales are any indicator of how quickly the new JL will leave dealer lots, there likely won’t be any deals to be had and even fewer used JL Wranglers available at a reasonable price. So if you are looking for a smoking deal on a new Wrangler, there may not be much of a reason to wait.

As far as used Jeep JK Wranglers go, it’s pretty well agreed by most enthusiasts that the ’12 to current Wrangler is more desirable and a much better buy than the ’07-’11 JK. The early 3.8L V-6 produces 85 hp less than the current 3.6L Pentastar V-6. It’s difficult and costly to try and get that much extra power out of the older 3.8L. Reliability suffers as well.

Since off-roading is not an overly important capability for you, you can save some money and steer clear of the Rubicon model. It has many features that will not be useful to you. There is no point in paying for those features. Consider a Wrangler Sahara. The Sahara trim offers many upfitted interior bits, and it’s a much more comfortable Jeep than the base model.

Off-Road Commander

First, I want to say I absolutely love Jp. It has helped fuel my love for Jeeps. I am a 23-year-old college student. My first car was a ’96 ZJ that I had for years, but I had to get rid of it because I did not have the funds to keep her moving. My new daily driver is a ’07 Jeep Commander Sport with the 3.7L. My goal is to keep her forever and turn her into my daily driver and four-wheeler on the weekends.

Now the task at hand: I want to install front and rear lockers at some point because I don't have a 4x4 low range on this Jeep, only a button to turn traction control off. I have been doing research, but I want to know what you would recommend. I want to be able to lock them from a button inside my Jeep. Any help would be greatly appreciated.
Matthew Hawkins
Baltimore, MD

Unfortunately, the ’06-’10 Jeep Commander XK was never fully embraced by off-road enthusiasts or the aftermarket. Oh sure, there are handful of people who have built them, but the vehicles simply don’t enjoy the abundance of aftermarket products that many other Jeeps have available to them. Your 3.7L V-6 Jeep Commander has the Quadra-Trac I full-time 4x4 system. From an off-road standpoint, it’s really the least desirable of all the 4x4 systems available on the Commander. Your Commander also has a C200 Mercedes 8.0-inch IFS high-pinion front axle. Out back, your Jeep has the more common Chrysler 8.25-inch solid axle.

I don’t know of any aftermarket selectable locking differentials available for the C200 IFS front axle. However, ARB (arbusa.com) offers an Air Locker for the Chrysler 8.25-inch in your Commander. The ARB Air Locker will give you the ability to lock and unlock the rear differential at will from inside the Jeep via a rocker switch.

You may have another option though. Some Jeep Commanders came with a four-wheel-drive system called Quadra-Drive II. This factory 4x4 system was actually very capable. Jeep Commanders with the Quadra-Drive II were really only limited by ground clearance. The low-hanging body and underpinnings of the Commander would cause it to get hung up on obstacles, but all four tires will still try to lay power to the ground. The Quadra-Drive II system included front and rear Eaton (eaton.com) EGerodisc differentials. They are essentially limited-slip differentials that have the capability of completely locking up automatically when the conditions allow. Each differential features a gerotor oil pump. This pump spins when differentiation between the right and left tires occurs. It pumps differential fluid and builds pressure behind a set of clutch plates, which are then forced into the differential gear, creating locker-like traction. Interestingly enough, it may be possible to adapt the front and rear Quadra-Drive II differentials into your Commander, although I have never heard of anyone making the conversion. Because these differentials use clutches that could wear out over time, it’s likely that the few used Quadra-Drive II differentials out there may be due for a rebuild. The good news is that if the EGerodisc differentials can be adapted to your Commander, you can also find them in the more-common ’05-’10 Grand Cherokee WK with the Quadra-Drive II option.

Full Coverage

I am a subscriber and was excited to see “Protecting an Investment” (July ’16). Unfortunately, I did not find the info I've been searching for over the past year. I was lucky enough to acquire a ’07 JK built by Kenny Hauk of Chambersburg, Pennsylvania, named River Raider. This vehicle easily has $80,000 or more upgrades from stock as do many of the vehicles you feature in your magazine. My vehicle (and I'm sure many of the customized vehicles you feature) is used daily both on- and off-road. My problem is I cannot find any insurance agent or company that will insure this truck for more than the stock value (collision and comprehensive), unless I commit to proclaiming it a show vehicle and drive only short distances to and from car shows. It's a Jeep, and I use it as a Jeep. Where can I get insurance for stated or appraised value that will protect my investment? I look forward to any advice you can offer.
Ron Day
Pipe Creek, TX

Insuring a Jeep with many modifications can be a tricky topic. Some insurance companies provide collision and comprehensive coverage that will automatically include some small amount for aftermarket parts. This typically maxes out at $1,000. If anyone has a policy like this, it’s always a good idea to take photos and keep receipts for the upgrades you make. Other insurance policies do not provide coverage for aftermarket parts.

For vehicles like yours with more extensive modifications, there are a few options. You’ll need to shop around for a policy with coverage for custom parts and equipment. It’s known as a CPE policy. Most drivers will pay only a few dollars a month for $5,000 coverage. However, you can’t buy CPE insurance by itself, you also must carry collision and comprehensive coverage.

Some insurance companies offer stated-value policies. A stated-value policy works a little different than a traditional automotive collision and comprehensive insurance policy. You and your insurance company agree ahead of time exactly what the payout will be if your Jeep is stolen or totaled. Your insurance premium is based on that figure. Stated-value policies are generally reserved for rare or one-of-a-kind custom vehicles, like your Jeep, where replacement would be difficult or near impossible.

Grundy (grundy.com) insures specialty vehicles as well as everyday vehicles. The company generally doesn’t require an appraisal, just images and a full list of parts. However, I’ve been told Grundy will not cover a vehicle that is used off-road, so this may not work for you. You’ll need to call the company for more details.

Other companies such as Motorsports Insurance Services (motorsports-insurance.com) offer policies for nearly every kind of vehicle imaginable. The company can probably find a policy that fits your needs.

Insuring a restored vintage Jeep can be just as difficult as insuring a highly modified Jeep. Companies such as Hagerty (hagerty.com) specialize in insurance coverage for older cars, including rare and uncommon Jeeps.

Smoothies

I am looking for a set of plain-looking steel wheels for my Jeep JK Wrangler. I am having a difficult time locating them. However, I see them all the time in Jp. The latest was on the olive-colored JK in the middle of page 12 of the Sept. ’16 issue. It looks like the plain steel Ram truck wheel, but that wheel has a 5.5x5 bolt pattern and won't fit without an adapter, which I would rather not use.

Another wheel I like is the one used on several of the Jeep concepts from Moab Easter Jeep Safari, among them the Africa and Shortcut.

Can you help me source these plain Jane wheels?
Sam Hoye
Via email

Fortunately, the basic solid steel wheels you are looking for are incredibly common. Several different manufactures offer them. The wheels pictured on page 12 of the Sept. ’16 issue are for a J8, which has a different lug pattern than your JK. However, Mopar (mopar.com) offers the same wheel in a 17x7.5 for the 5-on-5 lug pattern you need for the JK. It’s called the Winter/Off-Road Steel Wheel and is Mopar PN 52124455AB.

I believe the Shortcut concept has Detroit Steel Wheels (detroitsteelwheel.com). Other similar steel wheels include the U.S. Wheel (uswheel.com) Series 68, Stockton Wheel (stocktonwheel.com) 20 and 22 Series, Coker Tire (cokertire.com) Smoothie and Solid wheels, and the Cragar (cragarwheel.com) Series 69.

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