Traction and trail protection.
Project TraiLex, Part 1
Project TraiLex, Part 2
Project TraiLex, Part 3
Project TraiLex, Part 4
It has been a while since we visited our Project TraiLex on these pages, but the vehicle and the project have not been idle. We've racked up almost 8,000 miles on our Lexus GX470 since receiving it in January 2004. It has been on numerous road trips and we are pretty sure it's got more trail miles on it than any other Lexus on the planet. Perhaps some of you saw it 'wheeling around Moab during Easter Jeep Safari last April?Part of the delay in getting more info about the 'Lex onto these pages can be blamed on the two months of downtime we experienced last summer while we attempted to fit Air Lockers and lower gears into its diffs. The rear axle was a no-brainer.
It is a time-tested Toyota 8-inch V-6 pickup diff. An ARB RD23 Air Locker fit right in. The front proved to be our nemesis. It consists of a clamshell-design housing, much like a Tacoma or Tundra, with a reverse-cut ring-and-pinion and a lefthand drop. The difference is it features an 8-inch ring gear like a Toyota rear. The Tacoma and Tundra both sport a 7.5-inch front diff. An ARB is readily available for the 7.5, but nothing has been designed yet for the 8-inch version. We pressed hard on the Aussies to produce, but it seems there isn't much call for a front locker for a Lexus or a current-model V-8 4Runner (the only other rig that is currently using the 8-incher). Hummm, imagine that? There is rumor that the newly designed '05 Tacoma sports the 8-inch unit, so things could be looking up soon. Unfortunately, we are just way ahead of the curve.
We also ran into a dead end with our plans for lower gears. Stock cogs are 3.73:1s and we had hoped to drop down to 4.88:1s to offset our 33-inch Pro Comp Mud-Terrains and the extra weight and wind resistance of our trail-ready rig. After literally searching the entire world high and low for the pesky reverse-cut front, we were resigned to stick with the stock 3.73s. Again, the rear would have been no problem, as many ratios are available for the V-6 diff.
A close-up of the custom-built winch bumper built for the TraiLex. Material consists of 1/4-inch and 3/16-inch plate and 2x4 rectangular tubing. The finished bumper, along with the rock rails, rear quarter panels, and rear bumper were all powdercoated in a satin black. | 
Warn's new 9.5 XP 9,500-pound winch graces the front of TraiLex. This winch features one of the fastest line speeds ever at 7.6 feet per minute at a full 9,500-pound load. With no load, the rope will spool in at a whopping 38 feet per minute. We opted for the remote-control box, which we mounted under the hood. We had to notch the bottom of the grille to tuck the winch in tight so the bumper didn't stick out too far and approach angles could be optimal. Note the winch is also equipped with Warn's new 3/8-inch, 100-foot synthetic rope. This stuff has a stronger rating than equivalent steel rope, is much lighter, and much safer if it does break. It can also be handled with bare hands without fear of shredding yourself on frayed cable. | 
Sliced bread, anyone? We stole a trick from the rock racers and made our front skidplate from 1/2-inch cutting-board plastic. This is the same stuff that bread cutting boards are made of. It works amazingly well, sliding over every rock it comes in contact with. So far it has held up very well to TraiLex's 5,500-plus pounds of mass bearing down on it. It has definitely been used, as the Lex's ground clearance is still challenged by the trails we've driven it over. |
In keeping with our plan to keep TraiLex all mechanically Lexus, we resisted the itch to modify and graft another manufacturer's diff onto the Lexus' IFS. We buttoned everything back together, keeping the stock 3.73 gears and open front diff, and only adding an Air Locker to the rear diff. As it turned out, in executing our plan of running the Rubicon with TraiLex, a locking front diff would have been overkill. As you will read in a future article, the Rubicon was a piece of cake for the TraiLex. The combination of the factory Traction Control and the occasional use of the rear ARB provided plenty of grip to handle the 'Con.
The high gears have not proven to be a hindrance on the trail, either, as the torque converter easily makes up for the loss of gearing due to the bigger tires. But on the road, if any kind of hill is present, the five-speed automatic hunts constantly between Fourth and Fifth to enable the 5,500-pound 'Lex to maintain cruising speed. We find ourselves just leaving the gated shifter in Fourth most of the time. Gas mileage is horrendous at around 12 mpg. The poor 4.7 V-8 is just too overworked to push this tank around. A TRD supercharger would help the situation immensely, but proper gearing is the ultimate solution.
Turning to other modifications we have performed to TraiLex, we covered the suspension lift and cuts made to the sheet metal in Part 1 (July '04). Now you can see the finished look created by the custom-built front and rear bumpers, steel rear quarter panels and rock rails that replaced the cheesy running boards, plastic body cladding, and bulbous, mall-rated stock bumpers. All the metal fabrication, as well as the rest of the TraiLex buildup, was performed by Ned Bacon in Minden, Nevada.
The rear bumper is made from the same material as the front and features the same tow-ring holes--and the receiver hitch from the frame pokes through it. The gaps left in the quarter-panels by the removal of the big plastic rear bumper were filled with custom-shaped 1/4-inch plates. These panels are stout enough to support the weight of the rig with the Hi-Lift Jack. Like the front approach angle, the departure angle has been greatly enhanced as well. Note how we tucked the exhaust up high and ran the tip out through the right quarter-panel. | 
The rock rails have proved invaluable for 'wheeling the TraiLex over trails like the Rubicon--and still have rockers that allow the doors to open! They are made from 2x4 rectangular tubing and have had no trouble supporting the weight of the rig as it pivots around big rocks. | 
From this angle you can get a better view of the Yakima roof rack and the goodies in it. We mounted everything in the rack (except the Hi-Lift Jack) with simple ratchet straps and heavy-duty bungee cords. This method has made for easy, tool-less removal of everything and we have no rattles. The jack is bolted down utilizing Hi-Lift's optional mount. Due to ultraviolet rays breaking down the strength of straps and bungees, it's a good idea to check their condition often. |
Turning to things mechanical, this is the front diff, out and on the bench and split apart. That's about as far as we got with it. After measuring it from every angle, we determined that nothing could be done to enhance it with products currently available. An ARB Air Locker for the Toyota 8-inch diff will physically fit, as the diff is a regular Toyota 8-inch carrier. But the unit employs 52mm bearing caps, so ARB has nothing developed to get air into the Air Locker diff itself. | 
Here are both diffs, side by side on the bench. On the right is the rear unit, a standard Toyota 8-inch V-6-type diff. An off-the-shelf ARB Air Locker (PN RD23) was installed in it. Since nothing could be done with the front diff, we reinstalled it and hoped the factory Traction Control would be compatible with the Air Locker. It is, and TraiLex has performed better than our expectations when asked to rockcrawl over terrain that is a challenge for 33-inch tires and our available ground clearance. | |
A well-prepared trail rig should be equipped with the proper tools and accessories for getting it out of nasty predicaments. We've installed several products we've found to be time-tested and invaluable on any trail rig. The first is a Warn winch. TraiLex sports Warn's latest 9.5 XP, complete with the company's own synthetic rope. Up top, we installed a Yakima Mega Warrior rack, which is overloaded with a 33-inch spare Pro Comp Mud-Terrain and Trailready bead-lock wheel, a 48-inch Hi-Lift jack, a Pull-Pal winch anchor, and a Max Axe multipurpose tool. The Hi-Lift already earned its keep when TraiLex spit out a rear airbag during a run. The jack lifted the rig high enough to refit the bag, weld it in place and continue the run. Although we haven't needed the Pull-Pal or the Max yet, experience has shown us that having these trail tools in one's rig is invaluable when the need arises for a portable winch anchor or a shovel, axe, rake, or a hoe. We don't 'wheel without them. Check out the photos and look for the tale of the Lexus on the Rubicon soon. We have other nasty trail rides in store for TraiLex before Lexus pries the rig away from our grubby little hands, so stay tuned and we'll tell you all about them.
Project TraiLex, Part 1
Project TraiLex, Part 2
Project TraiLex, Part 3
Project TraiLex, Part 4