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Installing 23,000 Volt Offroad Lights

What are HID Lights?

Onboard Air
Converting a York
AC Compressor
to Pump Air

Warn 9500i Winch Installation

HEI Ignition
Installation & Review

Lockers, Limited Slips &
other Differentials Explained

Jeep Dana 300 TeraLow - 4:1 Gearset for the Dana 300 Transfer Case

Jeep Trans Swap
T-18A Transmission Rebuild & Short Shaft Conversion

For all the Jeep
Fans out there!

Offroad Reports

Jeeps at Rausch Creek
Off-Road Park

Wheeling in the Valley of the Ferns

Paragon Adventure Park
Rock Krawl

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Jeeps in Tellico NC

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2007 Jeep Wrangler JK Rubicon
An In-Depth Review of the JK, On-road and Offroad


Offroad Performance

This JK had it's first taste of the offroad on the rocks of Rausch Creek a few weeks before this trip so Mike had a good idea of it's offroad capabilities over the leaf sprung Jeep CJ-5, his other Jeep.  Mike detailed a lot of his thoughts on his experience at Rausch Creek on

"A few minutes into the trail the initial love for this Jeep developed.  I have little trail experience with a coil sprung Jeep and I have to say that they make all the difference.  The uneven terrain of a typical trail was completely absorbed by the coil springs.  The suspension of the new Jeep is very flexible, much like the JK's predecessor, the TJ.  We soon got into a rocky section, I pushed the rear locker button, put the Jeep in 1st gear, and with both feet flat on the floor I let the Jeep drive itself over the rocks.  The 4:1 low range makes for an excellent crawl ratio...The Jeep had no problem maintaining idle and momentum with no throttle input.  Only once the whole day I stalled the Jeep."

Much of our weekend in the Pennsylvania Mountains involved old, weathered and washed out logging trails with some specific destinations that offered their own unique challenges.  Mud, hill climbs, water crossings and rattlesnakes were among the encounters we had over the weekend.  As expected the JK performed flawlessly and made a lot of the challenging hill climbs and deeply rutted trails look easy.  We were 4 wheeling with a few other vehicles including a Jeep TJ Rubicon and a new 2007 Toyota FJ Cruiser, which was a lot of fun.  Lots of great trails, a rattlesnake and a porcupine encounter made for an interesting trail report, which can be viewed here, Wheeling in Rattlesnake Country.


Some of the highlights of the Jeep JK are Command-Trac® and Rock-Trac™ transfer cases, electric axle lockers, and electronic-disconnecting front sway bar, Electronic Stability Program (ESP), electronic roll mitigation, all of which assist performance offroad.


Stock JK Wrangler Clearances

Clearances P225/75R16 P245/75R16 P255/75R17 P255/70R18 LT255/75R17
Approach Angle
40.8 42.0 43.8 44.6 44.3
Breakover Angle
21.8 23.1 24.9 25.5 25.4
Departure Angle
37.4 38.7 40.3 40.6 40.4
Front Axle to Ground (inches) 9.1 9.6 10.3 10.6 10.5
Rear Axle to Ground (inches) 8.8 9.4 10.1 10.3 10.2


Rear tow hook location centered

Front tow hooks

Transmission: NSG 370 — Manual, Six-Speed Overdrive

Availability   Standard—All models
Description   Synchronized in all forward gears and reverse, multirail shift system with top-mounted shift lever
Clutch   Hydraulic actuation
Gear Ratios 1st   4.46
Gear Ratios 2nd   2.61
Gear Ratios 3rd   1.72
Gear Ratios 4th   1.25
Gear Ratios 5th   1.00
Gear Ratios 6th   0.84
Gear Ratios Reverse   4.06
Axle Ratio   3.21 Std., 4.10 Opt. (Std. on Rubicon)
Overall Top Gear   2.69 Std., 3.44 Opt. (Std. on Rubicon)



Transfer Case: NV241OR Rock-Trac

Type   Part-time, heavy-duty
Operating Modes   2WD High; 4WD High; Neutral; 4WD Low
Low Range Ratio   4.0:1
Center Differential Type   None


Room for a Hemi!


Engine Performance

Although the new 3.8-liter overhead valve V-6 engine, featured on all 2007 Jeep Wrangler models, has 205 horsepower and 240 lb.-ft. of torque, which produces more horsepower and torque than its predecessor, it still lacks the punch that is needed to thrill the driver.  When comparing the 3.8-liter to the 4.0-liter inline six-cylinder engine, the 4.0-liter Power-Tech in-line six engine achieved it's peek torque and horsepower at a much lower RPM, so to really feel the 3.8-liters full potential on the road, you have to drive it hard and even then it's slightly anemic.  This seems to be a common complaint among JK owners.  However from an offroad perspective, high RPM is not always desired for several reasons. For starters, high RPMs over immovable objects like rocks can break things.  Secondly, high RPMs generally means loss of wheel traction and loss of real control.  With the right options a JK will yield an impressive 73:1 crawl ratio, which will basically allow the Jeep to idle over the rocks and through the ruts with ease at a slow, controlled crawl.  Most of our 4 wheeling can be described as slow and controlled, or at least we try to be slow and controlled.  The Jeep JK is well equipped with a great combination of gear ratios to maintain a high level of control and finesse over the obstacles as factory electric lockers keep you moving and the push button front electronic sway bar disconnect helps keep the wheels on the ground.


Jeep JK Rubicon Craw Ratio

4.46:1 Transmission 1st gear (NSG 370)  

Final Crawl Ratio

4:1 Transfercase low range (NV241OR)  


4.10 Axle gear ratios  



Engine: 3.8-Liter, OHV, 12-Valve SMPI V6

Availability   Standard
Type & Description   Six-cylinder, 60° V-type, liquid-cooled
Displacement   230.5 cu. in. (3,778 cu. cm)
Bore x Stroke   3.78x3.43 (96x87)
Valve System   OHV, 12 valves, roller followers, hydraulic lifters
Fuel Injection   Sequential, multiport, electronic
Construction   Cast-iron block, aluminum alloy heads
Compression Ratio   9.6:1
Power (SAE net)   205 hp (153 kW) @ 5,200 rpm (53.9 hp/L)
Torque (SAE net)   240 lbs-ft @ 4,000 rpm
Fuel Recommendation   Unleaded regular, 87 octane (R+M)/2
Oil Capacity   6 qt. (5.7L) plus filter
Coolant Capacity   13.36 qt. (12.64L) Std.
Emission Controls   Three-way catalytic converter, heated oxygen sensors, electronic EGR and internal engine features

Meets Tier 2 Bin 5 (federal) and LEV 2 (CA) emission requirements



Offroad Performance Options


The Rubicon version of the JK is factory equipped with front and rear electronic lockers.  The X model and Sahara can be ordered with a rear locker.  Locker operation in simple and at the push of a button.  The lockers only work in 4WD low and under 18 mph (see the article: Locker Hacks).  The locker engage/disengage button is a two direction button.  Pressing the lower button once turns on the rear, pressing the lower again turns on the front (keeping the rear on - the front will only work if the rear is on)  Pressing the lower button a third time will turn the front off while keeping the rear on.  Pressing the upper button will turn all off.

Sway Bar

The Rubicon version of the JK is factory equipped with a front electronic sway bar disconnect.  The X model and Sahara can be ordered with a sway bar disconnect option.  Sway bar operation in simple and at the push of a button.  The sway bar works in 4WD low and under 18 mph (see the article: Locker Hacks).




Front   Live axle, leading arms, track bar, coil springs, stabilizer bar,
low-pressure (on 16-inch wheel packages) gas-charged shock absorbers—std.; Monotube high-pressure (on 17- and 18-inch wheel packages) gas-charged shock absorbers—std. Rubicon;
Electronic Sway Bar Disconnect System (ASDS) opt.
Rear   Live axle, trailing arms, track bar, coil springs, stabilizer bar, low-pressure (on 16-inch wheel packages) gas-charged shock absorbers—std.; Monotube high-pressure (on 17- and 18-inch wheel packages)  gas-charged shock absorbers—std. Rubicon



Vehicle Clearances

Clearances P225/75R16 P245/75R16 P255/75R17 P255/70R18 LT255/75R17
Approach Angle
40.8 42.0 43.8 44.6 44.3
Breakover Angle
21.8 23.1 24.9 25.5 25.4
Departure Angle
37.4 38.7 40.3 40.6 40.4
Front Axle to Ground (inches) 9.1 9.6 10.3 10.6 10.5
Rear Axle to Ground (inches) 8.8 9.4 10.1 10.3 10.2




Side by Side with the Jeep TJ Rubicon


Body styles and prices

  Price range   Trim lines
4-door SUV 2WD   $20,230 - $24,605   Unlimited X, Unlimited Sahara
2-door SUV 4WD   $18,485 - $26,595   X, Sahara, Rubicon
4-door SUV 4WD   $22,230 - $28,840   Unlimited X, Unlimited Sahara, Unlimited Rubicon


Drive wheels  
Rear or part-time 4WD  
2 front, 3 rear  
Engines available  
3.8-liter V6  (205 hp)  
Transmissions available  
6-speed manual
4-speed automatic
Fuel type Regular
EPA city/highway, mpg 16/19
Fuel refill capacity, gal 21.5
Dimensions and weight  
Length, in. 173
Width, in. 74
Wheelbase, in. 116
Curb weight, lb. 4,550
Percent weight, front/rear 50/50
Typical towing ability, lb. 3,500



Room for Improvement

Like anything nothing is perfect. The Jeep JK Wrangler is the most sophisticated Wrangler so far and possesses many features that makes modern vehicles safer and useful but there still is room for improvement. We have put together our list of what we think the Jeep should have...

50 more horsepower - come on Jeep! This thing is over 4000 lbs a small V8 or higher torque/horsepower V6 would be nice.

A locking mechanism to hold the rear gate open. Try holding the gate open on a side hill and get a cooler out of the Jeep.  Aftermarket?

Something to hold the front and rear doors open.  Again, Aftermarket?

More interior storage trays/compartments. There is no real good place for a pair of sunglasses.

110V converter power outlet in the cargo area. 

12V power outlet in the cargo area.

Lower ratio reverse - The 6 speed gearing is well suited for the Jeep but reverse seems a bit high.

Better defroster ducts - In the snow ice forms on the sides of the windshield AND the wipers freeze to the windshield when not moving because they are below the defrosters reach.

How about an optional on board air system?

Trail annoyances and oddities

The Jeep tends to run on at 2000 rpm.  For example, say you are running along in low range 2nd gear at 2000 rpm.  Let off the accelerator and the Jeep just keeps on going like it's on cruise control.  A touch of the brake or clutch and the Jeep slows back down, weird!  The fuel gauge - we were going slowly down the side of a long hill, after 10 minutes or so on the hill the low fuel warning alarm and indicator came on.  When we started our day the Jeep had nearly 1/2 tank of gas!  It couldn't be out?  We stopped and checked outside the Jeep for a leak but found nothing.  We reached a level part and after a few minutes the gauge started climbing until it returned to it's original position.  It turns out the sender is susceptible to extended down hill slopes and will report the fuel level being lower than it really is.

The Leak

The only complaint about the new JK is a leak that Jeep has yet to address properly.  The leak occurs when the Jeep is sitting still in the rain.  When you're driving, it doesn't leak.  So it seems to be a standing water channeling problem.

A visit to a "leak specialist" at the Jeep dealer but their acknowledgement of the problem was not enough and the leak continues and rain still drips in on the driver side door handle.  The problem seems to be coming from a seal above the windshield.

The "leak specialist" suggested that it was due to the retractable top actually being used. Not sure what they expect that explanation to mean.  But Mike has been looking at the seal and he thinks he has an understanding of what the problem is.   It seems it could be solved with a little silicone sealant under the seal.  We'll return to that leak at a later time.  Meanwhile Jeep has to get a grip on fixing this before they get a bad rap.  We're not sure on the numbers of how many Jeeps JKs have experienced this leak but we know this particular JK is not the only one. 



What is Jeep Trail Rated ?

The Jeep Trail Rated badge on the 2007 Jeep Wrangler verifies that the vehicle has been designed to perform in a variety of challenging off-road conditions identified by five key consumer-oriented performance categories: traction, ground clearance, maneuverability, articulation and water fording.

Jeep Trail Rated is an industry-leading methodology established by the Nevada Automotive Test Center (NATC) and Jeep Engineering to objectively measure and consistently predict off-road performance for all Jeep vehicles. Through a combination of natural and controlled field tests, as well as computer-simulated environments, Jeep Trail Rated provides a repeatable and consistent measurement of off-road performance for Jeep vehicles. Only Jeep vehicles are Trail Rated.

Jeep Wrangler JK Highlights

  • Off-road Capability – Increased ground clearance, larger wheels and tires, enhanced Dana front and rear solid axles, available next-generation Command-Trac® and Rock-Trac™ transfer cases, new electric axle lockers, and electronic-disconnecting front sway bar
  • On-road Refinement – All-new 100 percent stiffer frame in bending, 2-inch longer wheelbase, 3.5-inch wider track, lower spring rates, advanced shock tuning, increased jounce and rebound travel
  • Interior Space and Comfort – 4.6 inches more hip and 5.1 inches more shoulder room combined with additional 2 inches in couple, 1 inch in rear-seat leg room and 2 inches behind rear seat
  • Open-air Options – Dozens of different door, top and windshield combinations; new three-piece modular hardtop and innovative Sunrider™ soft top
  • Power and Torque – New 3.8-liter V-6 engine with 205 horsepower and 240 lb.-ft. of torque
  • Safety – Electronic Stability Program (ESP), electronic roll mitigation, dual-stage air bags, seat-mounted side air bags and Occupant Classification System (OCS)
  • Convenience – Available power windows and door locks, full-screen navigation system, 368-watt Alpine® stereo with MP3 capability, SIRIUS Satellite Radio



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