Mike Green 4x4 - Klune-V

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Basic Information

Klune-V Picture An Extreme Underdrive is an underdrive gearbox that bolts in place between the transmission and transfer case. we call it "extreme," because the underdrive multiplies your existing gear reduction by up to 4 times, rather than a usual underdrive of 1.2 times, or so. It is intended for extreme four-wheel-drive applications, rather than towing or gear splitting in a big truck. It works equally well with both manual and automatic transmissions.

Available in the "David" and "Goliath" models:

The "David"

The David crawler is intended primarily for short wheelbase applications where extreme low-crawl gears are desired for moving very slowly and precisely through difficult or very tight rock formations, and up or down waterfall-type obstacles. The emphasis is on precision, skill and finesse. While plenty stout, it is geared too low to be practical for hammer-down, tire-spin applications. (If you need more tire speed, simply shift the David into 1:1 ratio, leaving your transfer case in low range).

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The "Goliath"

On the other hand, the Goliath is intended for full-size, high-power hill climbing, mud boggin' pulling and tire spinning. Strength and unstoppability are the emphasis.

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Full Warranty

Both units are physically the same size, and have the same bolt pattern. These units are new-manufactured, purpose-built units, which come with a full two-year warranty. While similar to "dual transfer case" units in function, they are not built up from cut or sectioned used transfer cases.

Only Crawl Monsters Need Apply!

Klune-V Picture with Cable attached You're a serious enthusiast, which means you've gone down the road and know what you want. You've probably beefed up your suspension, expanded to 33-inches or larger tires, and added a locker or two. You're having fun, you're moving over the environment in all its forms and challenges. There's just one more step to go to maximize your rig extremely low gearing for extreme high adventure. With the Extreme Underdrive you've gone high tech and really low gearing. How low can you go?

LOWER...LOWER...

Bottom line, you'll be able to crawl up obstacles that previously were viewed as insurmountable. Here's a real-world example from our R&D department. Here's the scene.

"We're tracking in twelve vehicles looking for action in Surprise Canyon. We run into a Close Encounter of the Watery Kind, seven waterfalls that by the old book would require winches to conquer. We took on three of them just for the fun of it. That's the point, isn't it? Loose rock, slippery rock, big rocks, moon rocks we'll take them all on. Course, we had an edge. First we let the non-Extreme Underdrive vehicles have a go at it. One, a Jeep did manage one of the seven waterfalls, although he did get sideways and take several passes to make it across. The other guys without Extreme Underdrive packages said let's break out the winches. Not us in the Toyota Mini Truck and the 1977 Bronco equipped with the Extreme Underdrive upgrade. Both rigs crawled up three waterfalls totally unassisted and without any thrashing. Talk about a trial by fire rather water!

YOUR LOW GEAR JUST GOT REPLACED BY TWO MEGA-LOW RANGES

· And you still get to keep your existing low range, and good highway gears.

· Now Which Way Is Mount Everest?

· So You Can Crawl Over New Horizons What Else Does the Extreme Underdrive Offer?

· How about saving wear and tear?

· How about saving money?

· Extremely Low Gearing Means Reduced Body Damage and Mechanical Breakage.

· Time to stop or turn before that rock bites your quarter panel.

· By going slower, you control what you hit and how hard you hit it.

· Reduces shock loads on axles, drive train and suspension.

· Torque can be applied more smoothly, thereby less clutch stress.

· Simple physics that pay off in reduced repair, expenses and less down time.

LET'S GET TECHNICAL

What are the alternatives?

Sure, you can go another route to get low gearing. But they're called compromises for very good reasons.

You can change axle gearing to real low gears.

· Pro: You can get some lower gearing

· Con: You have to turn a zillion RPM at highway speeds. Not a good thing.

You can install a two-speed T-case with deeper gearing.

· Pro: It gets you somewhat lower and keeps highway driveability.

· Con: Loss of normal low range. And no super crawling.

What are the numbers?

The Klune-V Extreme Underdrive's multiple low range provides the most versatile gearing set-up available. If your vehicle is fitted with the "Goliath" Extreme Underdrive, you receive three different Transfer Case ranges:

· Normal High Range

· Normal Low Range

· An additional "crawl" range 2.7 TIMES AS LOW AS YOUR EXISTING LOW RANGE

If your vehicle is fitted with the "David" Extreme Underdrive, you receive four different Transfer Case ranges:

· Normal High Range

· Low Range

· A 4.0 Crawl Range

· Plus an EXTREME crawl range FOUR TIMES AS LOW AS YOUR EXISTING LOW RANGE! (for those super technical spots you want to really creep through)

What do the numbers mean?

The Extreme Underdrive provides the most flexible set of options available to respond to the wide range of environmental challenges you'll meet.

It also means you can actually use your off-roader on the road to get to the off-road site.

For example: Say you have a stock Jeep with stock tires. It turns about 2700 RPM at 65 MPH. With 33s and 4.11 axles (or 35s and 4.56 axles), still close to stock and fairly civilized. You will maintain decent highway operation. But if you switch to 4.88 or deeper gears, the highway ride heads toward the unpleasant zone. Worse yet, these super deep-cut gears rely on a relatively small and thereby much weaker pinion gear.

How're Your Mud Wrestling Skills?

Sand or mud driving usually requires high range or normal low range gearing. If you are missing your normal low range, a result of switching to a lower geared T-case, you'll find yourself stuck, literally, with an unsatisfactory choice of either high range (not deep enough) or a too-deep low range which restricts your tire RPM and as a result fails to pull you clear.

Loose lips sinks ships. Loose hill climbs pose other problems.

Normal low range (about 20-30 to one ratio) tends to work best for scaling loose hills. Scrambling helps maintain the momentum to keep forward-ascending motion. On the other hand, hard, technical rock crawling will be best enjoyed, and accomplished, using much deeper gears. If you venture onto "Sledgehammer" type trails, you¹d probably opt for a setting 130-225:1. Less than that and you'd be reaching speeds too fast for optimal control.

Remember our trip to Surprise Canyon and those slippery waterfalls?

"It's no surprise that we found a ratio of 145-225:1 best suited to keep you smoothly moving over the rocks and crawling up the falls. That's on the way up. Gravity wanted to drag us down; the Extreme Underdrive took us over the top. On the return trip, we got the best control from the 60-130:1 range. Now gravity tries to throw you down the mountain. Go too low, and you won't be able to scoot if you need to correct a potential end-do situation. Extreme Underdrive Super Crawling made it a walk on the wild side but with total control.

"So we had the water world experience in the canyon environment, and we looked for another dimension. Someone said Moab. They've got slick rock that gila monsters can't even hold onto. We blasted up Interstate 15 to Utah, then left it for some ledge climbing. Walking the ledge keeps you on your toes and the edges of your treads. The slick ledge rock responded best to 60:1 for climbing; slow enough for control, but enough momentum to get up the ledges you can't straight crawl up. Going down, we opted for 145:1 as you kind of "lowered" yourself down ledges, still keeping control.

"During transitions between more challenged sections, like on easier trails, we selected standard low range or 4.0:1 for best results. Extreme crawl is too low. Too many RPM, too much buzzing.

"Final summary: For serious Technical Rock, go for at least a 130:1 final drive."

So you want to go off the beaten path? Can you dance?

You're an experienced off-roader. You can walk the walk, dance the dance, but now it's time to learn to crawl Extreme Crawl. The traditional off-road driving method called "Off-road Dancing" involves coordinated tap-dancing on the brakes, clutch and gas pedal to wrangle your way through the tough spots. Good tricks of the sport and valuable survival skills, but it's time to enroll in Extreme Underdrive School for the latest in super crawl driving techniques.

For more information you can visit the Klune-V Web site.