The Lexus GX cruises quietly and efficiently on the highway, turning just 1500 rpm at 60 mph. At 2000 rpm, the speedometer was showing 79 mph, and the GX is still unstressed, riding along smoothly and quietly. The 6-speed transmission has a tall overdrive gear and the gears keep the engine right in the heart of the powerband.
The flexible 4.6-liter V8 allows for tall, efficient gearing without sacrificing responsiveness. With six close-set ratios available, the GX 460 displays an eager character when it comes to high-speed passing and full-power, on-ramp blasts. Lexus says the GX 460 can accelerate from 0-60 mph in 7.8 seconds and will do a quarter-mile in 16.6 seconds. We did not take the GX out to the track, but based on our driving, we would have no reason to quibble with those numbers.
On the highway, its ride is long-legged and effortless. In traffic, however, the GX feels more like the truck-based SUV designed for off-road use that it is. Small roadway repairs and heavily textured surfaces create a light jiggle that can be detected at around-town speeds. This we attribute to relatively low-profile 60-series tires on 18-inch wheels, and the thick anti-sway bars used to control the GX in corners. However, bigger impacts like potholes and speed bumps are readily swallowed up by the GX suspension, which is capable of absorbing the larger irregularities of unimproved roadways. Our route took us across a series of speed bumps, where we quickly noticed the faster we hit them, the better it felt.
The four-wheel disc brake system responds well to light pressure at the top of the pedal, which is how this family wagon would normally be driven. All-out stopping power is consistent with a vehicle designed tow up to 6500 pounds, when truly powerful brakes are a requirement. While there is some front-end dive upon very hard braking, more than the average sedan, given the nature of the vehicle, we'd consider front-to-rear suspension compression well controlled.
Cornering is quite good for a vehicle of this size, height and weight. Body roll is well controlled by the same stout anti-sway bars, allowing the GX to track through corners predictably without need for correction, and the stiff wheel and tire combination works to enhance stability. The GX 460 uses electric steering, which has had a reputation for relatively numb feedback characteristics, but this is not a sports car, and the packaging advantages include significant mileage gains. And, like some of the newer electric steering systems, this one seems more thoughtfully tuned, with a better range of power assist, leading to a nice turn-in feel and stable tracking through sweepers. The GX is not the kind of vehicle we'd be inspired to toss into corners, but the suspension travel is not so long as to create wobbles. We wouldn't call it nimble, but in ordinary use the GX is easy to drive and quite painless to operate.
The GX is always in four-wheel drive, a mode that was completely transparent to us as we drove. There is no sense of torque steer, and no scuffing or binding up during full-lock, low-speed maneuvering that might occur with part-time 4x4 systems. The use of a torque-sensing center differential allows the GX to continuously adjust power distribution from wheel to wheel as traction permits. Traction is further enhanced with the electronic traction system Lexus calls A-TRAC, so wheel slip is quickly controlled on surfaces like wet grass or slippery pavement. There was nothing extremely challenging about the weather or the dirt roads we addressed during our off-road driving, but the hills and service roads of the Vessels Ranch were enough to get the GX thoroughly dusty.
Finding a level spot, we actuated low range using a small lever just below the shifter, and saw that it nicked in and out of 4-Lo immediately. It's necessary to enter Neutral to access low range, but short of that, its additional 2.57:1 gear reduction is available practically on-the-fly. Because of the gearing, and the adoption of KDSS, the Lexus GX 460 is one of the very few mid-size SUVs with genuine off-road capability.
KDSS (Kinetic Dynamic Suspension System) is a remarkable electronically controlled system that unhinges one end of the anti-sway bars that would normally limit wheel travel. Limiting wheel travel is a good thing on pavement, but off-road, the opposite is desirable. KDSS offers a way to have the best of both worlds. It works automatically, without driver intervention, any time a wheel is lifted off the terrain while the vehicle is in low range. We've tested the system in the past on the Toyota Land Cruiser, and found it dramatically improves a vehicle's ability to avoid getting stuck while crossing highly irregular terrain.