[special-K]

3.08s is what these trucks use. 3.07 is a car ratio. What is the diameter of your tires now? This is all guess worth without knowing tire diameter, axle ratio, or what RPM you are running at 60.
It is true these trucks can run down the hiway as they are now just as well as when they were new. The issue is the younger drivers who don't know anything but experience with overdrive. There were interstate hiways in 67-72 and the speed limit was 70 mph most everywhere. Here in Maryland it is 5 mph slower than it was back then. The other issue is all the morons use overdrive as a way to drive faster. Screw them, they can change lanes and one requirement of driving that will never change is you are to look where you are going. The purpose of overdrive is to reduce wear and tear and reduce fuel consumption, but driving faster negates that. It's a good idea but not a requiement...and neither is the speed "limit".
I was driving my '95 yesterday wondering why overdrive automatics will jump to overdrive when you let off the gas at 40 mph. I mean really? Should be more like 50. That's how I drive a manual overdrive. But manuals require you to think. No wonder people are driving 50 mph in a 30 zone and tearing through parking lots like they are on the road. I usually take it out of overdrive in lower speed zones. You don't want overdrive running through town or neigghborhoods. It seems so many people are either on their gas or brakes and don't realize you can lift your foot and the car will continue to maintain speed for long distances, and if you are going up hill the car will slow down when you lift off the pedal. Ok, so I went into a rant