By G.R. Whale
There's no badge, no change in bodywork, not even an HD decal to visually separate the Suburban 2500 from its grocery-getter brethren. Only those clued in to such things will notice the higher rear ride height, smaller-diameter wheels with eight lugs or, if they're sitting low enough, the rear end of a working pickup truck.
Unseen Upgrades
However, under the square yards of Deep Ruby metallic paint, nary a mechanical component has gone untouched. The engine drops Active Fuel Management and gets an iron block for more twist and fewer ponies than the aluminum-block 6.0-liter V-8, yet it sounds identical and pulls to the same 6000 limiter-hence, no redline on the 6000-rpm tach.
An 80-series gearbox adds two gears, raising overall first from the best half-ton's 12.5:1 to almost 15.0:1 with taller overdrive (2.87:1 to 2.50:1) at the other end and a shift toggle on the lever. Despite having fewer ponies and nearly 800 more pounds to get moving than the last 6.0-liter half-ton (with 4.10:1s) we sampled, the six-speed showed its value by getting this very-low-mile unit to 60 mph 0.3 second quicker and through the quarter in the same time but with another 3.5 mph on the dial.
The rearend is a full-floating GM 14-bolt with an overload on the leaf-spring packs and no anti-roll bar; the standard wheels are 16x6.5-inch forged alloys with LT tires. Stuff like this has kept GM pickups hauling for decades, only now with a six-speed auto and variable valve timing.
Brakes
Inside, the rear-suspension architecture changes nothing around rear seats and wheelwells, so the cabin is the same as a 1500 except that you can't get the LTZ trim spec on 3/4-tons. This 1LT, loaded with 2LT and then some, is close to the topmost 2500. It sports four leather buckets and a $100-option three-person vinyl rear bench that split-folds 50/50. For another $1000, the 3LT package would add heated front seats and mirrors and Bose audio.
Six-Wheeler
To test how the Sub works as it was intended, we visited Sun Country Marine in Ontario, California, and hooked up a Chaparral Sunesta 264 deck boat. A bit over 26 feet long and with a no-permit eight-foot, six-inch beam, this had a 375-horsepower big-block with dual-prop outdrive, about 450 pounds of gasoline on board, and room for everyone in the Sub and then some, for on-the-trailer weight at 7400 pounds.www.suncountrymarine.com
www.chaparralboats.com
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Responsive analog gauges have the "pure pickup" look set into the LTZ-style single-glovebox dash, nicely melding function and design. There's a space for seemingly everything except the DVD headphones, an issue not unique to GM, and the materials are appropriate for intent and well assembled.
Sub-Mariner
We borrowed a 7400-pound boat/trailer combo for testing and while this is a ton shy of the max tow rating, it's exactly the weight you could tow if the Suburban was fully loaded. On a tri-axle trailer, tongue weight is moderate-it dropped the Sub just 0.75-inch at the hitch, and we bypassed the weight-distribution required by GM for this load in deference to the new boat trailer and lack of Reese SC or Equal-i-zer hardware compatible with surge brakes.