Test Drive

Photos and Story by Steve Sturgess | June 01, 2012

What’s really nice is the way the mDrive handles the unexpected, like a car suddenly slowing in front of the truck or an obstacle in a corner. You can focus on dealing with the situation, confident that when you walk on the throttle again, you’re going to be in the right gear.

We started out mid-morning and took a break after four hours. When I pulled up at the Customer Care Center, gates I felt fresher and more alert than I had at the lunchtime stop. That says a lot for the Mack, and speaks well of the transmission.

Rawhide option geared to owner-operators

The Rawhide edition brings an additional level of high style and comfort to the Mack Pinnacle Axle Forward model, resulting in a boldly distinctive truck.

Drivers who prefer traditional styling appreciate Mack’s Rawhide edition of the Pinnacle. The Rawhide has a set-forward front axle and a new hood to get the more aggressive, tall-fronted appearance.

The Rawhide interior features two-tone embroidered seats and soft button-tuck Ultraleather.

Introduced in 2008, the Rawhide features extra chrome in addition to the big square grille. A Texas-style bumper, undercab and sleeper stainless panels, big stainless visor and four chrome air horns add to the Rawhide’s luxury. Stylized chrome heated and lighted mirrors — each with a raised bulldog emblem — make a Mack statement.

The 7-inch bullhorn exhaust stacks mount between cab and sleeper in the established “large car” position, making the Rawhide unique in the Pinnacle lineup. Other models mount exhaust at the back of the cab.

The truck is available in 60- and 70-inch midrise sleepers, plus a daycab.

The Rawhide interior features Ultraleather and two-tone embroidered seats, complemented by a sleek dash housing Mack’s Co-Pilot driver display. Accent strips on the cabinets match the dash panel’s brushed nickel, and the two-tone pattern in the seats is continued in the sleeper in button-tuck.

Three MP engines, three families

The MP8 is the 13-liter engine in Mack’s lineup, which also includes the MP7 and MP10. The numbers derive from the displacements stated in cubic inches. The 11-liter MP7 is 670 cubic inches, the MP8 790 and the 16-liter MP10 970. All are single overhead camshaft engines with the camshaft drive at the rear of the cylinder block. This allows the fluctuating loads from the injector lobes on the camshaft to feed directly into the flywheel rather than along the length of the crankshaft, thereby reducing torsion in the engine and improving injection timing performance.

In our test truck, MP8 engine access was good, even with the added complexity of today’s exhaust gas recirculation systems. In fact, the new engines are considerably cleaner, externally, than the earlier E7, and components that might need service are easily accessible.

The MP8 at the 505-horsepower rating has a power density of 38.8 hp per liter, several hundred pounds lighter than similarly rated 15-liter engines. Torque rating is 1,760 lb.-ft.

All MP engines are available in three engine families: Econodyne, MaxiCruise and Maxidyne. The Econodyne personality is mapped for typical interstate applications with extended times at engine cruise speed — part-load, part-throttle applications where fuel economy is a priority. The MP8 in the Pinnacle we drove was an Econodyne and very much the highway tractor.

The MaxiCruise engines perform best on rolling interstates in on- and off-road applications. Maxidyne engines provide high power for low-speed, high-performance and severe-duty conditions, especially off-road.

Backing up the MP8 engine is the mDrive transmission, available exclusively in the Pinnacle. It’s a 12-speed, two-pedal automated mechanical transmission with a base torque input capacity of 1,920 lb.-ft. The mDrive is designed to integrate seamlessly with the MP7 and MP8 engines, and the gearshift is operated by an intelligent shift pad. The mDrive continuously monitors changes in grade (both up and down), vehicle speed, throttle position, acceleration, torque demand and combined vehicle weight.