Posted October 2nd, 2000

GMC celebrates its centennial in 2001. To mark the special occasion a new "Performance Biased Driveline" option package is being offered in the company's full-size, half-ton pickup - the Sierra C3.

The Sierra's C3 moniker is General Motors shorthand to indicate GMC's century of truck innovation (C) summed up in three qualities: performance, control and capability.

Some GMC folks also refer to the 3 to indicate that this is the third iteration of the Sierra since it was first introduced as a nameplate in 1988.

In any event, the highlight of the Sierra C3 is not that it's some glorified and gussied up anniversary model with several thousand dollars worth of extra of chrome, paint and leather but that it's a genuine truck with at least one innovation that we can think of that seems at least ten years overdue in a full size pickup - full time all wheel drive.

Remember the brief appearance of the 1991 GMC Syclone. Well, if you don't, the Syclone was a GMC Sonoma equipped with a turbocharged 280 horsepower, 4.3-liter V6 engine. It was a high performance hot rod that could outpace a Ferrari in the quarter mile and still accommodate a load of supplies from your trip to Home Depot. What made that feat possible, without tearing all the rubber off the rear tires, was the Syclone's unique full time all wheel drive system, a first in a compact truck, that kept all the wheels stuck to the pavement from the moment you pounded on the gas.

Two things remain surprising since the demise of the Syclone. First, the Syclone was built for a single year and sold only 2998 units. This is somewhat understandable since most of the public was unaware that the truck existed and those who did were probably quite hesitant to pay $28,000 for a compact truck no matter what its performance characteristics were ten years ago. Second, GMC, the rest of General Motors and the competition have never offered full time all wheel drive again in a pickup until the introduction of the 2001 Sierra C3 which is amazing when you consider the advantages of full time all wheel drive over traditional four wheel drive trucks.

Let's discuss the advantages of full time all wheel drive. GMC makes the claim that the Sierra C3 has the best on-road, wet or dry pavement handling performance ever engineered into a full size pickup. In theory its quite easy to agree with this statement.

Manually engaged four wheel drive trucks lack a component critical to full time all wheel drive trucks - a center differential. A differential is a set of gears that takes torque from the driveshaft and splits it evenly between the two output axles allowing them to rotate at different speeds. Without the center differential, when you engage a part time four wheel drive system, you wind up


Copyright July 2000,
By Michael Levine


90 degrees
Bore and Stroke:
4.00 x 3.62 in/101.6 x 92.0 mm
364 cu in/5967 cc
Compression Ratio:
325 bhp @ 5000 rpm
370 lb-ft @ 4000 rpm
Block/Head Material:
Cast iron/cast aluminum
Fuel Delivery:
Sequential fuel injection
Maximum Engine Speed:
5600 rpm
Emissions Controls:
Three-way catalytic converter, exhaust gas recirculation, positive crankcase ventilation, evaporative system

1st Gear:
2nd Gear:
3rd Gear:
4th Gear:
5th Gear:
Standard with Vortec 6000. 4-Spd Electronic Automatic (4L60 E-HD)

Exterior Dimensions Length:
227.7 in
Mirrors Open 78.5 in
Mirrors Folded 67.9 in
143.5 in
73.9 in
Track Width:
65.0/ 1651/ (front/rear) 66.0 in
Fuel Tank Capacity:
26.0 gal

Weights and Ratings
Payload (AWD):
1787 lb
6800 LB
Base Curb Weight (AWD):
5013 LB
Maximum Trailering Capacity:
8700 LB

Front Type:
Independent with Torsion bars
Rear Type:
Hypoid drive, semi-elliptic, two-stage multileaf spring
Rear Axle:
Shock Size:
(front/rear) 46/46 mm

17 x 7.5 in

Standard Type:
Michelin All-season steel-belted radials
P265/70R17 AL2



locking the front and rear axles of the truck so that they rotate at exactly the same speed. In a straight line you won't notice too much of a difference between part time four wheel and full time all wheel drive but when you go to make a turn the laws of physics catch up with you. Because the distance the front wheels travel while turning is not the same distance as the non-turning rear wheels you wind up 'scrubbing' the tires on the road as they seek to even the difference in speeds between the front and rear wheels. You'll feel this as resistance in the steering wheel during a turn. This is also the reason the truck manufacturers recommend you don't engage part-time all wheel drive on dry pavement - you'll chew up your tires fast. On wet pavement the tire wear problem for part time four wheel drive trucks is significantly reduced because the slippery surface acts as a lubricant to reduce the amount of friction between tire and road as it scrubs off the difference speed.

In an all wheel drive truck, no matter how you turn the wheels or in what driving conditions, there is no scrubbing resistance because the center differential, acting with the front and rear differentials, continuously transfers torque from any slipping wheel to those with a firmer grip.

The Sierra C3's all wheel drive uses a viscous coupling to automatically lock the differentials at the first sign of traction loss. The viscous coupling is composed of a strong and lightweight magnesium housing that surrounds the
two axles with a silicone based fluid. The viscosity of the fluid varies from the consistency of karo syrup to the consistency of silly putty depending on the load it is placed under. As slippage occurs the disc plates within the differential shear this fluid so that faster rotating plates, those connected to slipping wheels, transfer power to slower rotating plates, the ones connected to wheels with better traction, which 'locks' the differential. Because of their fluidic nature viscous couplings continuously transfer
torque at all times and in a such a way that the driver never notices an adjustment in wheel traction.

For those out there who have doubts about the durability or superiority of full time all wheel drive versus part time four wheel drive consider the following. The Range Rover and Hummer H1 use permanently engaged all wheel drive systems and both vehicles are among the most capable off-roaders available, bar none. On road you need only look to the German luxury manufacturers which consider full time all wheel drive an essential safety component, such as Audi's Quattro system.

On most all wheel drive luxury cars you will normally find a 50/50 power split between front and rear power distribution but because this is a pickup truck with an unloaded bed, the default split on the C3 is set to 38/62.

You've read the above concepts and theories, but now that we have driven the Sierra C3 we can also practically state that it is indeed the most capable handling pickup truck on the planet.

We drove the Sierra C3 from Santa Barbara, California up the coast to Morro Bay. On this trip we tested the truck on highways, surface streets, hilly roads with lots of twisties and the beach.

Of course the first thing we tried to do was step on the gas and see if we could get the rear wheels loose - which turned out to be next to impossible unless you wanted to lose control of the truck entirely. The C3 sticks to the road under all conditions, period.

On the highway and surface streets you aren't even aware of the all wheel drive's handling improvements, nor should you be unless you are in a defensive driving position trying to avoid an accident.

Between the highway and the beach we drove the C3 on a hilly mountain pass for a few miles. The truck was quite stable and under the driver's control at all times. No way was the rear coming loose - even while taking the turns at what fellow passengers might have considered aggressive speeds. In a two wheel drive truck you would have seen the rear end come around you on some of the turns. It's amazing the confidence you feel from the all wheel drive as it translates to the steering - not too much oversteer, not too much understeer but just right.

The beach was much the same story where we briefly drove the C3 right to the edge of the Pacific Ocean . Entering the beach we immediately executed a tight 180 degree turn with virtually no fish-tailing to speak of (no pun intended). Driving further down the beach we also tried slaloming the C3 around some piles of driftwood and seaweed. Again there was no oversteer on the sand beyond what would have been expected if we were on dry pavement with a two wheel drive truck.

Once we were on the 101 headed north out of Santa Barbara we took some time to appreciate the rest of the C3 in addition to its all wheel drive attributes.

GMC wants to position the Sierra C3 as an alternative to what they term 'international class' automobiles like the Lexus and BMW. So, for those folks who want a performance oriented vehicle in what is a decidedly nontraditional package, this truck is for you.

With its 6.0-liter V8 engine producing 325 horsepower and 370 LB-ft of torque, the C3 definitely has an international class engine. GMC claims the Vortec 6000 is the most powerful naturally aspirated engine in a half-ton pickup and its performance is indeed outstanding. Redesigned with aluminum heads for 2001 to save weight and provide freer-flowing intake and exhaust ports, the engine also incorporates a new low profile camshaft to take advantage of increased airflow into its combustion chamber. Acceleration is very good from both a standing stop and on the highways at cruising speeds.

While most international class cars come with the option of a five speed manual for performance enthusiasts, the Sierra C3 only comes with a four speed automatic, but what an excellent transmission it is. The well regarded 4L60-E transmission is taken from the Heavy Duty Sierra.

Now here is something you can't or wouldn't do with your Mercedes. The C3 arrives ready to tow 8700 lbs. out of the box. Though we didn't get to tow anything with the trucks we drove we have to believe that the C3's towing package combined with the all wheel drive is an unbeatable combination in a full size, half-ton pickup today. The only thing missing is the Quadra Steer option on this truck which is not available on the C3 for 2001.

Four wheel disc brakes are shared with the 3/4-ton Heavy Duty trucks and provide amazing stopping power.

The ride quality of the C3 on the highway is very good, especially for a pickup truck, but it you are used to driving a luxury sedan it is still quite a change. The C3 still doesn't translate road feel to the driver like a fine European sedan does. The ride doesn't seem quite as firm or the steering as precise. This opinion comes from a person who also drives a Quattro equipped Audi A4 so take it as you will. There is quite a difference in vehicle size to explain the differences in ride quality not to mention the C3's increased center of gravity and heavier weight.

Inside the difference between the C3 and the typical international class car decrease significantly. The C3 is filled to the walls of its extended cab with leather and its instrument panel is loaded with all sort of cool electronics. Heavy carpeting, good enough for your home, helps dampen NVH levels in the cabin.

One very annoying attribute inside the truck was its placement of the audio controls on the steering wheel. Set too far back it was almost impossible to adjust the volume or change stations without taking your hand off the wheel or bending your wrist into an awkward position.

The center console houses a trick little driver information center that records up to 15 days worth of trip information including mileage driven (split into business and personal mileage if you like), fuel economy and ranger. For those of you who give junior the keys to the C3 you can also look back at the top speed for a given day to make sure he isn't out drag racing.

A next generation OnStar system caps off the interior. Using telematics we were able to dial a phone number and hold a conference call in the truck all hands-free using our voice. Throw in some other cool voice recognition features matched up to your OnStar profile and you can also ask the OnStar system for stock quotes, sports scores and the latest news all tailored to your personal tastes.

On the exterior GMC continues to try and differentiate the C3 from the rest of the General Motors truck lineup. A newly revised grille with chrome trim and projector style headlamps adds to the truck's luxury class looks. The body colored front bumper with integrated fog lamps blends nicely into the rest of the truck. Running boards are standard along with rearview mirror 'puddle lamps' to help illuminate your step at night. Only three paint choices will be available: pewter, onyx black or polo green. A body colored tonneau cover is also standard on the C3.

We were disappointed by the lack of a crew cab C3 model. In today's market, especially if you are going after luxury car enthusiasts as your primary buyer, you need the versatility that four full size doors offer. A crew cab with the C3's capabilities would definitely be a class leading truck. We do believe that this will become an option in the not too distant future and we emphasize that it should happen as soon as possible.

As we look back at the Sierra C3 and its great abilities we cant help but wonder and hope that what happens with this truck will not be the same fate that awaited the Syclone. Like the Syclone the C3 has a very high price tag that we think will put it out of reach or send many buyers into sticker shock - $38,995. Is the world ready for a $40,000 half-ton, extended cab truck by the time owners drive out of the showroom? GMC believes that 10% of all extended cab trucks sold for 2001 will come badged as C3s. At the very least we hope that the all-wheel drive feature finally finds a permanent place within the GMC family of trucks as on option on all trim levels.

To sum things up, if you are a current luxury car owner looking to buy your first pickup, this is the truck for you. GMC has definitely created a vehicle whose comfort, safety and performance capabilities place it well within the luxury class.