What is on Farley’s mind other than thinking about his next bag of oats? Parked next to Farley’s corral is the new GMC Yukon Hybrid featuring GM’s 2-mode hybrid system. The 2008 Yukon Hybrid boasts a 332 hp, 6.0L Vortec V8, a NiMH 300V battery, two 60KW motors in the transmission, and nifty software that controls the whole caboodle. Not only can you pack in 8 passengers utilizing the 3rd row seating, but this 4×4 hybrid has the capacity to tow 6,000 pounds. Translation: mom can take the team to soccer practice during the week and dad can tow the family boat to the lake on the weekend.

I called upon Tony to perform an informal tow test just to see how well the 2-mode hybrid system works while pulling a big load up and down some hills. So, we hitched up his trailer and track car which adds up to over 4,000 lbs. The trailer weighs approximately 1,100 pounds and the track car weighs in close to 3,000 pounds. Our designated hill for the test had an 8 - 11% grade. Because the Yukon did not have a brake bias switch, the trailer brakes could not be connected and were not active for our test.

During our short test the Yukon Hybrid came through with flying colors. Uphill grunt was smooth and almost effortless. Controlling our speed going downhill produced no drama and the Yukon’s brakes had more than enough braking power to slow our rig heading downhill at 40 MPH.

This was only a brief test, so we couldn’t judge how hot things might get while towing a load on a longer trip. There is a quick information display incorporated in the gauge cluster. Along with the trip mileage and average/instant fuel economy numbers, the transmission temperature can be found. Since the Engineering folks at GM put in a huge effort to program and optimize the multiple transmission modes (EVT versus four fixed gears), it makes sense to have the ability to keep a watchful eye on the transmission before it melts down.

For those that appreciate a complex piece of machinery, the new transmission is an engineering work of art. The 2-mode hybrid transmission fits into the same space as a standard six-speed automatic. It contains two 60-kilowatt motors, and has four fixed gears, three planetary gear sets and four clutches.

In my opinion, General Motors’ game plan to create fuel efficiency where fuel efficiency is needed most was a great move. Especially, with today’s weak dollar and fuel prices reaching for the stratosphere. GM has plans to propagate the 2-mode hybrid system to the Cadillac Escalade, Chevy Silverado and GMC Sierra (crew cab versions of the pickup trucks) in the very near future.

And what were our fuel economy results for the Yukon Hybrid? GM claims the Yukon (aka Chevrolet Tahoe) Hybrid gets 20 in the city and 20 on the highway. After 500 miles of testing, and a couple of trips to the gas-n-go, we recorded an overall fuel economy of 17.8 mpg. Driving mostly on the highway without the trailer/race car gave us 20 -22 mpg. Our tow test was too short to get any real fuel economy numbers while pulling a heavy load.

Click on the link to read Twain’s full review of the Yukon Hybrid and its family-friendly features.