GM has also replaced the hydraulic steering pump with an electromechanical belt driven motor, replaced the steel hood with an aluminum one, and carved weight from the seats to offset the overall Two-Mode Hybrids' 400 extra pounds versus the conventional truck.
What you finally end up with is a V8 hybrid powertrain that’s optimized to perform at low and high speeds. And it returns over 40-percent better fuel economy in the city and up to 10% more on the highway, compared to a 5.3-liter equipped Tahoe.
Gary White, GM's vice president and vehicle line executive for full size trucks, says the Two-Mode Hybrid will only be available on Chevrolet Silverado and GMC Sierra Crew Cabs at Job 1 next year. The truck team still hasn't finalized the trim package, but it will probably be the LT level pickup.
One potential drawback for work truckers - the new pickups won't be quite the mobile power plants the Parallel Hybrid Silverados were. They'll be giving up the PHT's pure generator mode, that provided 1,400-watts of power for heavy tools plugged into the truck’s four 110-volt outlets."These (new) trucks will have a 110-volt outlet to run a computer or small SkilSaw, but they're not going to have as powerful a generator as was on the last truck," says Mr. White.
I drove the GMT 900 truck for about 20 minutes in fast and slow driving conditions. At low speeds, the big SUV drove golf cart quiet and smoothly fired up the V8 as velocity increased or power was needed quickly.
It was an eerie feeling driving something so large yet stealthily quiet. However, I found starting and driving the Tahoe in electric mode at commute speeds to be easier to get used to than my experience driving the old PHT Silverado, where you could feel the V8 rumble to life as the truck moved away from every stop. Motion and road feel from the low rolling resistance tires dampen the rumble effect in the Two-Mode Hybrid.
The standard navigation display in the Tahoe has the hallmark Prius-style monitor, which shows you the mode the truck is operating in and what engine components are being blended together during driving. Mr. White says it's likely that half-ton hybrid buyers will be given the choice of ordering the navi-unit as optional equipment because of price sensitivities in the segment.
Other expected differences between the Tahoe/Yukon and Silverado/Sierra. The pickups won't get the lower ride height and front clip mods the SUVs have, but the haulers will get the full-on hybrid badge treatment and low rolling resistance tires.
There's also no tow/haul mode for trailering and moving heavy cargo. Instead, the EVT constantly adjusts RPM to pick the optimal load and speed combination depending on load conditions.