Custom 4x4: Toyota 79 Series Land Cruiser

When you have a boat and trailer combination that tips the scales at close to 3500kg, you need a vehicle that won’t raise a sweat pulling the skin off a rice pudding. A Land Cruiser Double Cab is a good place to start… but it ain’t perfect.

For starters, it’s only available with a manual gearbox and, when you’re hauling a heavy load, a self-shifter can make life much, much easier. Oh, and with that much weight behind you, a little more grunt is never going to go astray either.

When Steve Booth splurged on his new 79 Series GXL Double Cab last year, he was already quite familiar with Toyota’s TDV8. “I had a single-cab before,” Steve explains. “If I was travelling by myself it was fine, but if I had somebody else in the car there was nowhere to put your bag or anything else, so I thought a dual-cab would be perfect. We don’t generally use it with anyone sitting in the back, but it’s a good place to pile all the stuff and still have plenty of tray space at the rear.”

When Steve drove his new Cruiser off the dealership floor, he already had plans to flick the standard five-speed manual gearbox and replace it with a self-shifter. Towing with an auto offers many advantages: less driver input required, no slipping of the clutch, less wear and tear on driveline components and the added benefit of the torque converter’s torque multiplying effect. And as for the TDV8 engine, Steve also had plans to give the Cruiser a hefty performance boost to make towing his boat even easier.

To look after the power and transmission upgrades, Steve would call on the expertise of three different companies spanning three different states. Then he’d go to a company in a fourth state to build the ute’s custom aluminium tray.

Steve lives in Victoria, so he didn’t have far to go to get Mark’s 4WD Adaptors to swap out the five-speed manual ’box for a GM 6L90 six-speed automatic. This transmission is ideally suited to Steve’s towing requirements; not only is it rated to 1200Nm of torque with a GVM of 6803kg and a GCM of 9525kg, it also features three selectable shift modes designed to make towing a breeze: Automatic, Tow Haul and Manual. Tow Haul mode changes the shift characteristics so the transmission will hold gears for longer. Manual mode offers full manual shifting while locking up the torque converter.

To say Steve’s impressed with the GM auto would be an understatement. “Our 200 Series; it’s up and down through the gears like there’s no tomorrow,” he says. “It’ll hold fifth for a while and then fourth and then back to third… it’ll be all over the place – whereas the GM transmission’s got a Tow Haul button, so it locks the torque converter up straight away and it’ll actually hold back and it’ll just keep pulling instead of revving.”

Another advantage of the GM six-speed auto is its taller top gear. Unlike the notoriously low standard gearing, Steve says with the GM auto, the engine’s only ticking over at 1800rpm in sixth gear at 100km/h. This makes it a much more relaxed highway cruiser, with or without a trailer hitched.

The Mark’s 4WD Adaptors’ six-speed auto kit includes everything required, including a new bell housing, transfer case adaptor, computer and wiring loom, transmission cooler, full-size auto brake pedal, auto shifter, transmission lines and more. Importantly, it also includes a PWR radiator with an internal transmission oil-cooler. The whole package retails for $19,500, including installation and an engineer’s approval.

Even with the new six-speed auto, Steve knew that towing would be a hell of a lot easier with more power and torque on tap, so he sourced a bigger aftermarket turbocharger through Perth-based GTurbo. This was matched with an off-the-shelf intercooler kit from Adelaide-based Cross Country 4X4.

This trick-looking intercooler features twin 10-inch electric fans on its underside for optimum airflow. It’s also much bigger than the standard intercooler and has a custom 660x300x76mm tube and fin core and distinctive sheet-metal tanks.

Another standout feature under the bonnet is the custom-made air box, which was made by Moonlight Custom Fabrication & Welding in Perth. Moonlight also looked after the stainless-steel pipework through to the aforementioned aftermarket turbocharger.

Managing all this new hardware is a Unichip engine management system. The result?

Even before the current larger pipework was fitted to the intercooler, a dyno test indicated Steve’s 79 Series was pumping out around 180kW and 850-900Nm at the wheels. When you consider that Toyota claims a modest 151kW and 430Nm at the crank, that’s one seriously massive improvement!

When he’s not towing the boat Steve has an XTRAIL camper that he uses for camping on the Murray River. With its newfound grunt and slick-shifting auto ’box, Steve says of the Cruiser towing the camper: “Yeah, it doesn’t really know it’s there.”

Not really a hardcore off-roader, Steve describes his four-wheel driving as “mostly touring”, which is why other modifications to this rig are not nearly as radical as the upgrades to the engine and driveline.

An ARB GVM-upgrade (now 3780kg) suspension kit was fitted before the vehicle was registered, and other ARB gear includes the bullbar, side rails and ARB Intensity LED driving lights.

Befitting the vehicle’s dual towing and touring duties, the CSA Raptor satin-black rims are fitted with Cooper Discoverer ST Maxx rubber. “We’ve got them on our 200 Series as well and they’ve been a good tyre,” Steve says. “A good compromise for a bit of touring and around town grip as well.”

As for the custom tray on the rear, Steve had to once again look interstate to find the solution to suit his requirements. “The tray was custom-built in Cairns of all places, by a company called Norweld,” Steve says. “I couldn’t really find anyone in Victoria at the time that was interested in doing something custom with aluminium. I’d seen some work that Norweld had done, and they said ‘yep, we can build it without the car here, no worries…’”

The Norweld tray incorporates a half-canopy toolbox as well as integrated toolboxes behind the wheels and a slide-out drawer at the rear. The half canopy toolbox houses an ARB fridge, behind which sits an Optima battery and a Redarc dual-battery management system. There’s a shelf above that’s big enough for bulky items such as swags and the like.

Steve keeps recovery gear and a few spares in the rear drawer, “a bit of stuff that it doesn’t matter if it gets a bit wet,” he says. As for the side boxes: “They seem to be more waterproof than the centre box does; they’ve been under water and haven’t had any water in them.”

Ensuring long-distance comfort, the front seats have been replaced by Recaro items with longer seat bases in them. The sound system has also been upgraded with a double-DIN touchscreen Eclipse head unit incorporating mapping software, while an amplifier boosts the signals to upgraded aftermarket speakers.

Other interior modificationss include a couple of neat Autron gauges on the A-pillar that display amp draw on the dual batteries, a ScanGauge trip computer on the centre console, and a remote-head GME UHF radio.

When you want one vehicle to perform several tasks, it doesn’t always turn out the way you envisaged, but thanks to a lot of forethought and planning, Steve’s more than happy with how his 79 Series Cruiser performs, no matter what task is put in front of it.

“It’s pretty well turned out the way we would have expected,” he says. “There’s plenty of power there; it’ll tow the boat in sixth gear at 100 kays, it sits on 1800 revs and it pulls hard on hills and stuff like that – our 200 Series certainly doesn’t do that!”

The next time you find a vehicle you really like, but when you look over the spec sheet and find that it doesn’t perfectly suit your requirements, you could always take a leaf out of Steve’s book and modify it until it does.

If you plan it right, and don’t mind searching far and wide for the best solutions, you could end up with a rig that fulfils its intended function as well as this one.