Long the leader in the fullsize SUV segment, General Motors isn't letting any grass grow between its toes with its next generation of fullsize SUVs. These photos of a cladded 2014 Chevrolet Tahoe were snapped just outside GM's proving grounds. Interestingly, the badge on the grille underneath the mesh covering is a prominent oval, indicating GM may have been hoping to fake-out spy shooters into thinking it's a Ford. However, a Chevrolet bowtie can be seen on the wheelcaps under the tape and there were Toyota Sequoia and Ford Expedition comparison vehicles accompanying the prototype.

Since the addition of a six-speed automatic to the lineup in 2009, the GMT900-series SUVs have been near top-of-class in terms of fuel economy. Reports of an eight-speed automatic transmission and direct-injected fifth-generation small block V-8 power for the new Tahoe (known internally as K2UC) and the Yukon(K2UG) indicate GM intends to remain a class leader in this increasingly important area. Although the eight-speed is certainly in the cards at some point, availability constraints may have the big SUVs launching with six-speeds.

In what may also be a concession to efficiency, the test mule appears to retain the GMT 900's solid rear axle. Most fullsize SUVs, including the Expedition and Sequia, have independent rear suspensions, which are favored by some manufacturers for allowing greater flexibility in interior packaging. However, the marginal frictional losses inherent in CV joints of an IRS may have outweighed the potential benefits. In addition to less mechanical drag, solid rear axles are generally considered more robust for towing and hauling duties.

New all-aluminum small block V-8s equipped with direct injection are a given, likely in the same displacement as the current 5.3 and 6.2-liter fourth-generation Vortec engines with a possible 5.5-liter variant. GM may still have some surprises up its sleeves, however -- some reports have suggested a diesel option could be offered along with a hybrid model, though the GMT900 hybrids haven't set any sales records. Also unknown is whether GM will field a turbocharged V-6 option to counter Ford's popular EcoBoost powertrain, which may soon be offered in the Lincoln Navigator.

GM clearly has high hopes for the new Chevrolet Tahoe, Suburban, GMC Yukon/XL and Cadillac Escalade models, having invested a total of more than $500 million in its Arlington, Texas plant since 2009. GM is overhauling its entire fullsize truck and SUV lineup within the next 18 months and the new SUVs are expected to be second or third in line, behind the new Chevrolet Sliverado and GMC Sierra 1500, with the 2500 and 3500-series HD trucks and fullsize SUVs following.