2008 Ford F-250 Super Duty Crew Cab 6.8-L V10 4x4 5-speed auto
2007 GMC Sierra 2500 Crew Cab 6.0-L V8 4x4 6-speed auto 3.73
0 to 30 mph
0 to 40 mph
0 to 50 mph
0 to 60 mph
0 to 70 mph
0 to 80 mph
Three-Quarter-Ton 1/4-Mile Assessment:
of the three-quarter-ton trucks, it's GMC's new 6.0-liter Vortec Max
V8 / 6-speed heavy duty transmission combination that has the best
setup for the level 1/4-mile. The gear ratios perfectly match the
engine's torque curve. It was also the only truck to get above 80-mph
with a trailer when we ran it at MPG over a mile long road course.
interesting, though, is Dodge's HEMI gearing. Both our Ram and
Sierra had 3.73:1 final drive ratios, but check out second
much higher in the Ram, at 1.67:1, than in the Sierra, at 2.36:1. There
wasn't much of a time difference from 0 to 40-mph between the trucks
unloaded, but as soon as the 10,500-pound trailer was hooked up the
0 to 40-mph delta grew to almost a full second. The HEMI fell behind
because it lugged against that 1.67 ratio. We think the results would
have been much closer if the HEMI had the same, or near-identical,
spacing as the Vortec Max's cogs.
the way, Dodge is the only truck of the three that uses the same transmission
with their gas engines in 1500, 2500 and 3500.
we compare the GMC against the Ford, the 4.30 final drive ratio in
the Super Duty handicapped that truck unloaded but definitely helped
it while towing - at least at the start. The two trucks swapped the
lead with each other twice, up to around 50-mph, before the
GMC's six-speed transmission and its excellent gear spacing once again
proved decisive - enabling a V8 to beat a V10.
a trailer tells a different story with transmission gear spacing and
final drive ratios - which is the reason final drives are lower in
three-quarter-ton and one-tons versus half-tons.
you buy a heavy duty today, one of the few performance decisions still
under your control is determining the final drive ratio - particularly
for a gasser. There isn't a dramatic difference in fuel economy between
a 3.73 and a 4.10, but towing acceleration and less tranny downshifting
are going to make the 4.10 a better choice for a gas truck. If you're
purchasing a diesel, it's not going to be as important.