There is a lot of god info in this thread and some varied opinions.
The 35 MPH max speed deal was a unit choice and was probably driven by local road conditions (think unpaved tank trails at Camp Swampy) or accident history and was not a service wide policy.
Most major commands used a 50 MPH max speed as a matter of policy or regulation. This was not usually a safety issue. It was done to allow some "catch up speed" for the inevitable times when the convoy did the accordion thing. If the unit march speed was at or near the redline, no one could catch up without over speeding the engine or breaking the then 55 MPH national speed limit.
As already stated the engine was originally designed for agricultural use and will tolerate working at the red line for extended periods very well. However, that assumes the valves are correctly adjusted, the cooling system is properly maintained, the injector timing, air filter, oil system, fuel filters and fuel system are all correct etc. If you and the truck are new to each other, how do you know?
I have no issue with running the rucks for an extended time at or near the red line but I have spent the last 34 years around them. Especially for someone without a good bit of experience with these trucks and with the particular truck they are driving I would not advise pushing it that hard.
The military services select and train operators, not drivers. The distinction is important. We should be operating the truck, not just driving it. The sounds, smells and vibrations coupled with our personal knowledge of the particular truck will tell us more and give us far more information or warning of impending issues, than the gauges will.
I'd recommend a couple of hours of moderate speed operation with frequent checks (per the Operators Manual's checklist) before pushing the truck hard.
If you show up at the vehicle location, perform some checks, jump in it and drive without stops you are asking for trouble. Typical issues that won't show up when the truck is stationary are things like bad bearings, rear main seal leaks, air compressor leaks, flat spots in belts that turn into cord ruptures etc. If the truck is new to you I'd recommend a stop within 10 minutes to check wheel bearings, tire inflation, lug nuts and the rest of the truck and then stop every hour until you are really comfortable with the truck's running condition.
Lastly, consider these two facts.
All of the MVs currently available to us as collectors were desinged when either road conditions or the national speed limit kept vehicle speed lower than today. The wheels, tires, brakes and steering were all designed for lower speeds.
The stopping distance of an unloaded truck is often longer than the stopping distance of a loaded truck. The brakes are designed to stop it loaded and if you hit them hard when it's empty you dramatically increase the probability of locking the brakes and loosing control. This is one of the things stressed in heavy vehicle operator training. When most of the vehicles around you can stop in a much shorter distance than you can it really increases the chance of you parking on a car.
Lance
