Part I: Toyota Drivetrain Transplant
Exactly four years ago in the Dec. '03 issue of 4WD&SU, a bone-stock '86 Samurai was transformed into a capable trail rig suitable for moderate rockcrawling in a buildup entitled "Suzuki Extremes." Modifications to the Samurai included a Rocky Road Outfitters JP-Eater suspension, 35-inch tires on Eaton beadlocks, heavy-duty bumpers, Toyota axles, ARB Air Lockers, and several other goodies that made it quite the little beast. Since that story ran, the Samurai has conquered some fairly difficult trails, including the Rubicon, Dusy-Ershim, and the Hammer Trails of California just to name a few.
Over the past few years, the Samurai has endured a few operations for repairs and to enhance performance. A Davesport rollcage was installed along with JAZ race seats and five-point harnesses shortly after a rollover incident. Next, the wheelbase was lengthened just a bit to prevent such incidents from reoccurring.
The Samurai performed like a champ on lots of trails and rockcrawling challenges, but there were always obstacles that the guys with built Toyotas and Jeeps could handle with ease while the Samurai struggled. It was obvious that the Samurai's short wheelbase and lack of gearing, horsepower, and tire size were its shortcomings. Although the wheelbase had been extended some 7 inches for a total of 87 inches, the really capable rigs were still at least a foot longer, making them more stable on extreme angles.
The Samurai's gearing also left something to be desired. The axles were well-equipped with 4.88 Precision Gear gears and ARB Air Lockers. A double-Low 4.16 transfer case was installed as well, but that just wasn't low enough for the Samurai's anemic 1.3L four-banger to push 35-inch Mickey Thompson Baja Claws over the larger rocks. To remedy the problem, a Trail Tough Rock Block gear-reduction box was installed, doubling the ratio of the 4.16 T-case, giving the Samurai a workable 148:1 crawl ratio. The Rock Block configuration worked fairly well and actually enabled the Samurai to tackle some pretty tough stuff, but the vehicle still lacked the gearing it needed for extreme terrain. After considering the options, it was decided that the entire drivetrain and perhaps the engine should be replaced with something entirely different.
Replacing the engine in addition to the drivetrain was a very involved and expensive prospect, not to mention the hassle of trying to pass strict California smog tests with an engine transplant. After examining various drivetrain alternatives, one setup in particular began to stand out. The same drivetrain that the Toyota guys were running could be adapted to the stock Samurai engine with a kit from a Canadian company, SOS (Suzuki Only Supply), whose parts are available through Rock 4X Fabrications.
Most hardcore Toyota wheelers run a dual Toyota transfer-case setup in addition to lower gears in one or both of the cases. This setup can be configured several different ways to provide ultra-low gearing, and the cost of the setup is very reasonable compared to other options. Another selling point is that the Toyota transmission can be adapted to several popular engines, including the Suzuki 1.6, Suzuki Swift engine, VW diesel engine, or even a Toyota powerplant. This would allow the drivetrain to be dealt with first, and as the budget allowed the engine could also be replaced. Best of all, the Toyota drivetrain is tough, featuring a solid, "married" T-case design, and uses commonly available parts.
The drivetrain would be Toyota, and the engine would be left alone (for now). This plan looked fairly simple in theory, but as the details were reviewed it quickly evolved into a fairly complex project. Installing the Toyota drivetrain would not be a simple bolt-on job but would require a bit of creativity, some fabrication, and the removal of stock sheetmetal.