- Apr 7, 2006
2007 Chevrolet Tahoe LT: In the Autoblog Garage Day 5
It's now time to bring our review of the 2007 Chevrolet Tahoe LT to a close. We've looked over the fresh sheetmetal and crawled around the all-new interior, but before rendering a verdict we have to get behind the wheel and see if the redesigned SUV has the driving dynamics to back up its looks.
[Click through for pics, commentary, and our final thoughts on the new Tahoe...]
Under the Tahoe's hood, we find the GenIV version of the company's long-running line of small-block V8 engines. The 325 HP 5.3L engine features Displacement On Demand (DOD), which shuts down half of the cylinders under light-load conditions. This reduces the pumping losses, thus improving fuel economy. We observed 15 MPG while driving in "mixed" conditions (what we considered to be a fairly even mix of urban, two-lane highway, and expressway travel), and pulled down just over 17.5 MPG while cruising at 75 MPH on the expressway. Those are great figures for a full-size SUV, but we didn't exactly feel like we were saving the planet, either. The Tahoe is capable of running on E85 (despite our tester's lack of a yellow gas cap), but as ever, the trick remains finding a gas station that carries it.
The 5.3L delivers sufficient power, although there's no doubt that it's tasked with moving around a substantial amount of mass. The engine makes some interesting noises as it goes about its business, with an almost musclecar-like exhaust note replacing the wheezing sounds we expect to hear from this type of vehicle. In fact, some may even find the V8 rumble to be a bit too much for their liking (not us, but hey...).
Backing up this fine engine is GM's 4L60E four-speed automatic. While we expect most of our readers to focus on the number of available gear ratios (or lack thereof), that really wasn't the main source of our complaints. Rather, it was the transmission's complete and total lack of willingness to downshift that frustrated. We've experienced this gearbox in several dozen other applications and haven't had this problem to the same extent, so we chalk it up to matter of electronic calibration problem rather than a fundamental flaw of the hardware. Regardless of the cause, expect to file paperwork (in triplicate, signed, and notarized) if you want to trigger a 4th to 2nd downshift. Putting the trans into the Tow/Haul mode helped slightly, but then the upshifts were delayed far longer than prudent (probably the result of being optimized for, uh, towing and hauling). On the positive side of things, the shift feel was generally quite good. If we owned one of these, it'd be receiving an immediate reflash of the transmission shift points.
Rounding out the drivetrain is GM's Autotrac transfer case, which offers the driver a choice of 2WD, full-time 4WD (achieved via the use of a progressively-locking clutch pack, not a center differential), and part-time 4WD Hi and Low modes. We think that it's an ideal arrangement for such a vehicle, although having an available low range seemed a bit odd for a vehicle that will drag its air dam on parking-lot curbs.
A solid axle is hung from a set of four trailing arms out back, while the front of the truck receives an updated version of GM's SLA independent suspension. Gone are the torsion bars; in their place lie a set of coil springs. Aluminum lower control arms replace the previous generation's ferrous bits, and front-mounted rack-and-pinion steering equipment is used in lieu of the recirculating-ball gearbox that has been a GM hallmark for several decades.
Over most road conditions - even the Midwest's famed cratered spring pavement - the GMT900's improved rigidity almost makes it possible to ignore that one is driving a body-on-frame vehicle-- believe it or not, the solid rear axle behaves itself in virtually all situations. It's possible to upset the Tahoe's composure with the right sequence of backroad bumps and ruts, but for the most part, the overall structural integrity is a huge improvement over previous generations. We were also pleased with the spring and damper rates, which do an admirable job of keeping the big truck under control even when thrown around like a car. Get too crazy, and the Stabilitrak stability control system will step in with authority to issue a reminder that this isn't a sport car, and should not be treated as such. We elected not to push things further to see if the system indeed works as claimed, keeping the shiny side up.
Quite simply, the Tahoe steers with precision not expected of a 5800-pound SUV with a waist-high center of gravity. We'd prefer less power assist - the efforts seemed tuned towards those who like to hold a cell phone in one hand, a cup of coffee in the other, but at least every bit of wheel movement translates into a meaningful response from the vehicle.
The same magic has been carried over to the brakes, which may possess the best pedal feel we've ever experienced on a mass-market body-on-frame SUV. The takeup is immediate, with virtually no lash, and the amount of boost provided dead-nuts perfect. It does take a fair bit of shove on the pedal to bring the Tahoe to a rapid stop, but that's to be expected with nearly 3 tons of mass (we prefer this situation than to have pads that are excessively grabby). As usual, GM's ABS system works well, although the lack of traction provided by the OEM tires ultimately limits the effectiveness of the braking hardware.
So, you ask... what's the verdict? While GM has done an admirable job of improving every aspect of the Tahoe's performance, the operational envelope of full-size SUVs was long ago described by Sir Issac Newton. The main competition for the Tahoe and its stablemates isn't so much the Ford Expedition or Toyota Sequoia, but rather the laws of physics. Viewed in the context of its full-size SUV competition, there is little question that GM has hit a home run, and we think it will deservedly continue to command the lion's share of its segment.