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The 2020 Ultimate Adventure Long Range Jeep #UA2020

Part 1: Assembling the Drivetrain

Verne SimonsAuthor, Photography

In the past we would cover the buildup of the yearly Ultimate Adventure Build in the pages of your favorite print magazine. With the changing times we decided to do a multi-part buildup on the vehicle with shorter stories for online as the build came together. Still, we like details, so now we are regrouping the information and adding detail to it for a more magazine like series of tech articles on the build. So, if this info looks familiar, you're not wrong, but keep your eyes peeled, because there are more details and info on the build within this story and those to come. Much of the info we couldn't add to the shorter multi-part buildups is here.

Long ago, all over the world jeeps helped the Allies win World II. During the North African Campaign, mostly in the Sahara Desert, MB and GPW jeeps modified by the British SAS as fast attack vehicles inflicted much damage on their foes. These jeeps would rush into an area, wreak havoc, usually on Axis air bases, with vehicle-mounted twin Vickers K machine guns, and then disappear back out into the desert. Often these SAS jeeps were modified for these fast attack missions. They were sprayed in a flat sand color, fitted with extra fuel, water, parts, and iconically, all but the two center grille slats would be removed from the grille, supposedly to aid in airflow and thus engine cooling. The history is great, and there are tons of images of ragtag SAS soldiers riding in decked-out jeeps in books and on the internet.

The history of these successful hit-and-run raids by the SAS was set in motion by another group of explorers who, prior to the war, explored the Sahara as one of the last areas on earth to go unmapped. This group was led by a British scientist named R.A. Bagnold who'd spent his free time before the war, with a few friends, exploring the unmapped portions of the Sahara, usually in modified Model T and Model A Fords. With the beginning of World War II, Bagnold and others first formed the Long Range Patrol, or LRP, that would later become the Long Range Desert Group, a reconnaissance group that would teach and inspire the British SAS in WWII, the guys in jeeps.

What does any of this have to do with Ultimate Adventure 2020? Well, other than a general interest in off-roading history and paying tribute to those who wheeled before us, not much. Truth is, editor Christian Hazel and tech editor Verne Simons have been discussing building this project vehicle, an SAS-inspired Jeep, since 2012, but the time wasn't right until now. And as you know, when it comes time to build a project vehicle for Ultimate Adventure, we like to find a theme to run with for the build, and building a highly capable adventure-based vehicle that pays tribute to the SAS and LRDG and those men who spent time in jeeps in the desert during WWII risking life and limb makes about as much sense as anything we can come up with.

Our plan: to make a modern-day Jeep that would be the envy of any and all desert-bound soldiers from WWII. Our starting point are some Jeep parts, a tub of a Jeep Wrangler LJ and a stretched TJ frame, and to that end we will call the project the Ultimate Adventure Long Range Jeep or UALRJ. Our plan is to use the vetted and quality parts provided by our sponsors (that allow the Ultimate Adventure to occur) to build a vehicle that stands out, is capable and reliable, and can take us through the weeklong on- and off-road adventure that is Ultimate Adventure 2020, come what may.

Under the knife in this, Part 1, are the bits that will make up the drivetrain including a Cummins R2.8, a brand-new AX-15 transmission from Quadratec, a clutch from Centerforce Clutches, flywheel and bellhousing from Quick Draw Brands, a Magnum underdrive from Offroad Designs (ORD), and a pair of our favorite crate axles, Ultimate Dana 60 axles from Dana Spicer.

This is the starting point for the 2020 Ultimate Adventure Long Range Jeep (UALRJ) that will pay homage to the SAS Jeeps from WWII in North Africa, the Long Range Desert Group (LRDG), and more. Before we can start on the build, we need to strip down the body and chassis to get it all ready for the new parts that will make the Jeep one of a kind but easily reproduceable.

It's a LJ body on a stretched 2003 TJ chassis, and no part of it has been on the road in a long time, but it makes for good bones to start a project that will work well on-road and off. Don't worry, it won't look like this for long. We have some tricks up our sleeves to make it much more retro and a real tribute to the SAS and early desert explorers.

We are using our Bendpak 10k asymmetrical vehicle lift to remove the stock axles. They would work just fine for some smaller projects, but we know this Jeep is going to be big and bad. The stock Dana 30 and Dana 44 will make room for a pair of Ultimate Dana 60 axles.

As goodies began to arrive for the project, things began to take shape. Quadratec has been selling some of the best parts for Jeep builds and restorations for decades. This brand-new AX-15 transmission assembly from Aisin Warner is an original equipment part. It's perfect for many different re-power projects like ours. What you get from Quadratec is a brand spanking new, fully synchronized, medium-duty transmission. It comes with lower shifter tower and a reverse switch already installed. Gear ratios for the AX15 are: 3.83 for First, 2.33 for Second, 1.44 for Third, a 1.00:1 Fourth, and a 0.79:1 Fifth gear. That will keep our Jeep happy while on the road and on the trail.

You've seen us use the Cummins R2.8 turbodiesel before in UA projects, and that's because it's a no-brainer for a vehicle like this. The engine comes with a now two-year or 2,600-hour limited warranty, and it makes 161 horsepower and a whopping 310 lb-ft of torque. This engine comes with way more than other crate engines including most of the fuel system (you just need a feed and return fuel lines), accessories, a turbo, computer, wiring harness, and more. Sure, you could piece together a junkyard-fresh Cummins 4-BT or struggle along with a used small VW-based turbodiesel, but this engine is just the right size for most medium-duty 4x4s (some of our past projects have weighed in at about 6,200,pounds, and this thing moves them well). And it should yield great fuel economy and it's all new not a hodgepodge of dubious used parts.

If you know off-roading, you know how important gearing is, and there may be no better combination of parts than the Offroad Designs (ORD) Magnum Underdrive coupled to one of ORD's prepped NP205 transfer cases. This system is nearly bulletproof behind just about any powerplant (it's massive overkill for ours) and offers gobs of gearing options. It has 1:1 and three low ranges. First the Magnum adds an underdrive of 2.72:1, and the NP205 is good for a 1.96:1 low-range ratio. Combine the two for a whopping 5.33:1 low range. That gives us great gearing for mud, sand, and technical rock crawling. Also the NP205 prepped by ORD allows you to shift the front or rear into neutral at any given point allowing front and rear dig maneuvers.

To join the Cummins R2.8 to the Ax-15 transmission, we will employ a Quick Draw Brands adapter bellhousing and flywheel and a Centerforce II clutch. Quick Draw makes lots of adapters and other cool parts for Cummins R2.8 swaps and more, and Centerforce is an iconic brand when it comes to on-road and off-road performance clutches and is a family owned American company. The clutch is intended for a 1997-1999 Jeep Wrangler TJ with the 4.0L. The Quick Draw Brand's flywheel is a Cummins R2.8 flywheel machined for the Jeep clutch.

We did, however, discover that the Quick Draw Brand's flywheel was not countersunk for the factory-style bolts included with the Centerforce clutch. This means that you either have to use non-shouldered 5/16 Grade 8-bolts to hold the clutch and pressure plate to the flywheel or you'll have to counterbore the bolt holes about .25 inch for the shoulder of the Centerforce included Grade-8 bolts. The pilot bearing, clutch fork, and clutch fork mounting provisions were supplied by Quick Draw, and we added in a Centerforce throwout bearing again for a 1998ish 4.0L powered Jeep Wrangler.

Ultimate Dana 60 axles from Dana Spicer are next to indestructible. We've used them in the past in several UA project vehicles, which we've beaten time and again without issue. The front axle uses a high-pinion ring gear that is 10 inches in diameter. That's huge. Both axles have 3.5-inch axle tubes, 35-spline chromoly axles, 1350 yokes, huge brakes, and more. The front axle also uses gigantic SPL-70 steering U-joints, and Warn locking hubs.

For the 2020 UALRJ we are going with the optional 4.88:1 axle gears and Eaton E-lockers (ARB air Lockers are also available with 4.88:1 and 5.38:1 gearing, E-Lockers are available with 3.73:1, 4.10:1, 4.88:1 and 5.38:1 ratios). Our axles are set up for use in a JK, but these axles are also available without mounts, or for JL and JT.

The Quick Draw bellhousing is literally built like a brick outhouse. It's thick, fits perfectly, and will sustain years and years of abuse. And with it in place and the Centerforce clutch and pressure plate mounted to the Quick Draw Products machined flywheel, the whole shooting match can get assembled. Don't forget the clutch fork, pivot ball, fork retaining clip, throwout bearing, and supplied clip to secure the throwout bearing to the clutch fork.

Here's most of the drivetrain roughly in place between the framerails of our Jeep. Next time we will talk about the suspension the Jeep will use, how we fabricated the motor mounts, and how we built the transmission/transfer case mount and more

 

Historical Photos for Those History Cuffs

 

Members of the expedition standing by cars, from a collection of lantern slides made to illustrate a paper by Major R.A. Bagnold on "A further journey through the Libyan Desert," read by W.B.K. Shaw on May 29,1933, Libya. Artist R.A. Bagnold. (Photo by Royal Geographical Society via Getty Images)

War and Conflict, World War Two, pic: circa 1944, Western Desert, North Africa. A New Zealand patrol of the Long Range Desert Group, part of the British Army, pictured resting and "brewing up" for drinks. This mobile force of small parties of men, heavily armed, covered thousands of miles in the Sahara Desert. The group's Chevrolet 1 1/2-ton vehicles are parked in the background. (Photo by Paul Popper/Popperfoto via Getty Images/Getty Images)

Lieutenant Edward MacDonald (foreground) sits at the wheel of his Willys MB -ton Jeep with Corporal Bill Kennedy manning the twin-mounted gas-operated Vickers K machine guns beside him and the rest of the heavily armed patrol of L Detachment Special Air Service (SAS) Brigade on January 18, 1943 somewhere in the desert of North Africa. (Photo by Major Geoffrey Keating, No 1 Army Film & Photographic Unit/Hulton Archive/Getty Images)

The Campaign In North Africa 1940-1943, The Axis Offensive 1941 - 1942: A Special Air Service jeep patrol is greeted by its commander, Colonel David Stirling, on its return from the desert, January 18,1943. (Photo by Capt. G Keating/ Imperial War Museums via Getty Images)

A war veteran talking to young WWII reenactors in a reproduction WWII SAS Willys MB jeep during World War Two militaria fair. Our plan is to mimic this type of SAS re-creation with modern modifications to make the UALRJ the pinnacle of what it can be for ultimate adventuring. (Photo by: Arterra/Universal Images Group via Getty Images).

Source:

Sponsors:
Cummins, 800.286.6467, www.cummins.com/engines/repower
Dana, 800.621.8084, spicerparts.com/applications/crateaxle
Falken Tire, www.falkentire.com/
IH Parts America, 530.274.1795, www.ihpartsamerica.com/
Offroad Design, 970.945.7777, www.offroaddesign.com/
onX Offroad, onxmaps.com/offroad-app
Quick Draw Brand, 513.446.9654, quickdrawbrand.com/
Quigley Motor Company, 800.233.9358, quigley4x4.com/
Skyjacker Suspension, 318.388.0816, skyjacker.com/
VooDoo Offroad, 844.866.3661, www.voodoooffroad.com/
Warn Winch, 800.543.9276, www.warn.com/

Other Sources:
Centerforce Clutch, 800.932.5882, www.centerforce.com/
Quadratec, 800.745.6037, www.quadratec.com/