Klune-V Extreme Underdrive

Flashback F-150 Meets ""Goliath""

Nov. 01, 2005 By Norm Lenhart
Flashback F-150 moves further into the "multi-purpose" realm with the Klune-V Extreme Underdrive Planetary Reduction box. Klune has opened up the world of rockcrawling to the full-size market, and there'll be no going back!
If you think the Ford vs. Chevy rivalry is amongst the greatest feuds of all time, you should take a stop by the air conditioned, and neon lit offices of Off-Road.com, while we're discussing upgrades to Flashback F-150. It usually goes something like this..... Patty.... "You better figure out what you want to do with that truck. You've got desert parts, rock crawler parts, and mud parts. Make up your mind!" Eddie.... "Norm, face it. It's a Disco truck. It has a chrome roll bar!" (says the man with flared "Renegade" street fenders on his Wrangler...but I digress...)

Yup, it's a beast. With a machined aluminum housing, and huge gears within, the "Goliath" can handle well over 1000 horsepower on the transmission side. Add suction cups to your tires, and walk up walls. Simple really....

But the comments came fast and furious when I told them I had a Klune-V Extreme Underdrive on the way, and slated for installation in the large red Ford. "You're putting a WHAT in there? It ain't a rockcrawler!" "Well", I asked, "Why not?" I mean after all, a little rockcrawling now and then is good for the soul. It goes well with the Detroit Lockers and 4.56 gears in the axle housings, 35 in. Goodyear MT/R's, and that Superlift 4 in. lift flexes pretty well. It even falls under the description of "off-roading" when you look it up.

While I take a lot of good natured ribbing over my truck (and who doesn't?), the fact remains that few people consider full size trucks as rock crawling material. On the other hand, there are a lot more reasons for serious gear reduction than just crawling rocks.

There's not a lot of complexity to the Klune box. Since our combo doesn't need any extra adapters, or mods to the transmission shaft, installation woes should be minimal at worst.

Over the past several years, several gear set transplants and other solutions have been developed to provide massive gear reduction in Jeep and Toyota applications. We've seen dual transfer case swaps, retrofitted gear sets, and dual transfer case setups "with" retrofitted gear sets. All the while, us "big truck" guys have been left out of the loop, dreaming over the crawl ratios we couldn't have, or building our own dual case setups from scratch.

It seems like forever, that we've had to console ourselves knowing that our bulletproof NP 203 / NP 205 cases with their ...ah..."low range" (of about 2 to 1) wouldn't be grenading any time soon behind the torque of our 350+ inch engines. Consoled yes, but not too happy about it. There's really no end to the versatility that a lower crawl ratio can provide a full size, or in fact, any rig.

That's where the Klune-V Extreme Underdrive planetary reduction box comes in, and suddenly "How slow can you go?" doesn't apply just to the Jeep/Toyota set anymore. We big guys can now crawl with the best of'em. When Klune Industries decided to get into the off-road world, they had a little experience in building high quality, highly specialized parts to draw from. The aerospace contractor has a list of customers in the aeronautic / military field that reads like a "who's who", of this countries national defense program: Raytheon, Lockheed, Boeing, Northrup Grumman...the list goes on.

It's not a big stretch to imagine the kind of product they could , and did, bring to the off-road world.

Shifting is accomplished via Morse type cable. It's either "in", or "out". Here's a hint..."In" is where the fun really begins!

Klune-V's Planetary Reduction box is available in two models, the "David", and the "Goliath": The "David": The "David" is designed for the short wheelbase crowd, where driveline angles are a major concern. A true "Rockcrawler" box, the "David" features reduction in the 4 to 1 range at the pull of a lever - in addition to your transfer case gearing. You can probably imagine the numbers obtainable with an SM420 and low axle gearing. The "Goliath": The Goliath is the box for the big trucks, and application where the ultra low gearing of the "David" may be more a hindrance than a help.

Geared at 2.76 to 1, The "Goliath" provides plenty of gear reduction for high horsepower applications, and is designed as a more rounded product. Hill climbing, mud bogging, and similar applications are The Goliath's bread and butter, but it still provides the big rigs with more than enough reduction to "rock".

  • Includes mount and choice of cable operated or direct lever shifter.
  • Available with 21, 23, 27, 31, 32 and 6 spline input
  • Available with 21, 27, 28, 31, 32, 6 spline male and 10 spline female output
  • Ratio: 1 to 1 high range; 2.7 to 1 low range
  • Rated at 1300 ft/lbs. torque input, 3510 ft/lbs. out in low range
  • Rated in excess of 4000 ft/lbs. torque in high range
  • Length 6.5”
  • Weight 40 Lbs.
The shifter for the Klune Extreme Underdrive is simple, and reliable. Small in size, and equipped with plenty of cable, you'll be able to mount it just about anywhere.

Reduce Me The Klune-V Planetary Reduction Box is a chameleon of sorts, providing the benefits of the multiple gear selection / reduction available in a traditional dual transfer case set up, without the overall length/weight problems associated with it. It also exceeds the reduction available in a 4 to 1 x-fer case gear swap, while adding to your gear choices.

Perfect? Is anything ever? There's only one dent in Klune's armor we can find thusfar, and it's unavoidable in a product of this type. As an add-on unit, you'll need new drivelines, but for those of us requiring kind of functionality the Klune box provides, it's an inconvenience we're willing to live with. When you consider the complexity of a dual x-fer case installation, the Klune-V is dirt simple by comparison, and less expensive in the long run to boot.

Because Flashback is a "general purpose" truck that will get crazy on occasion (occasion being the operative word there), we didn't really need the reduction of the "David" box. The 2.70ish gearing of the "Goliath", coupled with the 1.94 to 1 low range of the NP 205 we're swapping in appeared to be a far better choice. Considering that exceeds a "4 to 1" gear set anyway, we aren't going to complain. Add that to the new 4.56 gears we just bolted in the axles and we're in Crawl City.

Built? ...you could say that..... Planetary gear sets are well known for vicious amounts of torque multiplication, so the housing that holds them had better be more than up to the task. When you start feeding more than 400 cubic inches worth of power through anything, it has to be built tough. We shouldn't have worried. The billet aluminum housing of the Klune Goliath box is rated to handle well over 1000 horsepower - far more than this motor will ever throw at it. The quality of the box was evident from the time we opened the shipping crate. From the sheer weight of the Goliath, to it's machined surfaces, to the Morse type cable that actuates the boxes' low range, to the mounting hardware, none of it was anything near "cheap".

It's that type of workmanship that has resulted in exactly "Zero" failures of the Goliath since Klune began testing it three years ago. Torque Applied As of this writing, the Klune Extreme Underdrive Planetary Reduction box is available for a variety of applications, but the NP203 isn't one of them. The model we received was among the simpler to install - A Ford C6 / NP 205 that doesn't require any additional adapters, or changes to the transmission output shaft. Depending on your app, the mileage will vary.

Fortunately, Klune offers a host of adapters to fit the most popular combos. Even with a C6, and the "high" first gear it has on-board, the numbers are impressive. 2.76 x 1.94 x 2.76 x 4.56 = 67.38 to 1 at full converter lock. Now factor in the 2 to one torque multiplication of the converter before stall, and you're at 136 to 1! Not too bad for a full size truck with an automatic. As stated above, the "add-on" nature of the box results in several gearing choices. For example.... First gear, x-fer in high, Klune box in low =
2.76 x 1.00 x 2.76 x 4.56 = 34.73 to 1 (69.47 W/converter slip) First gear, x-fer in low, Klune Box disengaged =
2.76 x 1.94 x 1.00 x 4.56 = 24.41 to 1 (48.82 to 1 W/converter slip) And since we'll soon have a manual valve body in the C6, we will have the benefit of full control over 2nd and 3rd as well as low, for serious gear choices.

Now that we have the Klune Extreme Underdrive Planetary Reduction box in our hot little hands, it's time to get it into the hot (not so little) truck. Be sure to stop back next month as we take Flashback F-150 ever deeper into the realms of true "multi-purpose" functionality!

For more information about the Klune Extreme Underdrive, be sure to check out...
7323 Coldwater Canyon Ave
North Hollywood CA
Phone: 818-503-8100
Fax: 818-764-3199 And tell'em Off-Road.com sent ya' !

Off-Road.com Newsletter
Join our Weekly Newsletter to get the latest off-road news, reviews, events, and alerts!