JK Wrangler

JEEP’S original and evergreen icon – the Wrangler range – came in for a complete revamp in early 2007 with the JK series, making it only the sixth to do so since 1945.

The big news surrounded the introduction of a four-door five-seater body style known as the Unlimited, devised alongside the all-new two-door four-seater wagon.

Both come in three versions – base Sport, well-equipped Renegade and the new super-serious off-roading Rubicon edition.

Not messing with the proven formula, Jeep retained much of the trademark Wrangler styling cues, such as the removable full or half-frame doors and hardtop and soft-top options.

The windscreen still folds down, but is now curved instead of flat, for quieter and more refined progress.

Almost everything else changed too, from the body and interior to the ladder-frame chassis, suspension and drivetrains, with big gains in space, performance, safety, refinement and on-road driveability.

Other than packing in an extra 523mm to the two-door Wrangler’s 2424mm wheelbase, as well as two extra side doors, the Unlimited is otherwise identical to its shorter sibling.

Yet despite the latter dimension, rear-seat legroom, hip room and shoulder room balloons considerably, as does cargo space.

Australia was one of the first markets in the world to receive a diesel Wrangler.

The 2.8-litre common-rail turbo-diesel four-cylinder CRD unit delivers 130kW of power at 3800rpm and 400Nm of torque between 2000 and 2600rpm.

Petrol powered Wranglers switched to a new 3.8-litre overhead valve V6 producing 146kW at 5000rpm and 315Nm at 4000rpm, banishing the heavy 130kW/305Nm 4.0-litre OHV six-cylinder unit that dates back to the old American Motors Corporation days – Jeep’s owners before Chrysler’s 1987 takeover of the marque.

Both powerplants utilise a six-speed manual gearbox, while the diesel’s five-speed automatic goes two better than the petrol’s four-speed auto transmission by offering an extra gear as well as an alternate second gear ratio according to whether the vehicle is changing up or down, for smoother and more efficient progress.

Two types of transfer cases are available.

All bar the Rubicon models, which are inexplicably petrol-only for now, feature Jeep’s second-generation Command-Trac part-time, two-speed transfer case utilising a 2.72:1 low-range gear ratio. It is claimed to be stronger, more durable, smoother and more efficient in operation.

Meanwhile, the Rubicon adds Off-Road Rock-Trac to its artillery, an upgraded 4x4 system with a two-speed transfer case and a 4.0:1 low-range gear ratio.

Over the TJ, the JK brings improved ground clearance, to match its impressively short front and rear overhangs.

This Wrangler sits on a fully boxed frame that is twice as stiff in bending, and 50 per cent torsionally stiffer, as previously. This helps dynamic and refinement properties, and provides a better base for severe crash impacts from all directions.