PART 6, --- Where the expression, MEXICAN OVERDRIVE came from, I do not know. In my case it just seems to have always been there.
About 50 or more years ago, when the trucks were all low powered and the hills were higher, steeper and not cut down as they are today. Without all the power assists that are now commonly used, such as high horsepower, engine brakes, power steering and spring brakes. You had to rely on multi transmissions with the maximum number of gears squeezed into the box, to give your engine more assistance to pull you up and over these steep, and high hills, and to help you control your downhill descents.
The odd time you would come to a fairly straight but long downgrade that could tempt you to kick it out of gear and run loose. This procedure was commonly called Mexican Overdrive.
Trucks were usually geared for 65/68 mph max speed. The condition of the roads and the available horsepower really didn't give you much of a chance to make good travel time. When you came to a high hill with a fairly straight down run, temptation would sometimes take over your common sense, and put you into a dangerous situation. It could pull you like a magnet to cut it loose and just go.
There have been countless times when drivers have let her go. There have also been drivers who did not make it back alive, after losing control and having this activity change into a wild runaway.
This type of incident (Mexican overdrive) happened to me in 1957, on the building of the Trans Canada Highway along the North shore of Lake Superior, in the mountains.
In my case, I was driving a "B-61" Mack pulling a tanker with hot liquid asphalt. This particular hill was a couple miles down to the bottom on curves, and just south of Terrace Bay, Ontario, Canada.
I was in a hurry this day, as we were being pushed pretty hard. I broke over the hill and said to hell with it and cut her loose. The hot liquid was sloshing around in the tank and was becoming unstable to control, pushing me from side to side and picking up speed by the second. The truck was going too fast to get it back into gear. It would normally run at about 68 mph, flat out. I was well beyond that, and the Speedo would max out at 80 mph. The Speedo needle went beyond 80 and kept going completely around again. Between the 15 and 20 mph, the Speedo cable broke and the needle dropped straight down and just sat there swinging freely, pointing down. (Is this an omen, pointing to where I would end up?)
The brakes would not do anything but smoke and fire, they were useless. The truck started to shake and vibrate so bad that it took both hands to try and hold it steady. I went around a couple bad curves on the way down and had the feeling that this was my last ride. I barely made the curves and started to climb uphill, and that was when the vibration on the front end started to smooth out again. One of our other trucks, going the other way, saw me coming and pulled over onto the narrow shoulder, otherwise we both would have connected and ended right there. It was that close. It was an old narrow high crowned road with barely enough room to pass at normal speeds.
I began losing speed up the other side of the hill, and when I was slow enough to get it back into high gear, I would be going about 70 mph. I finally got stopped at the top of the hill, and sat for about 1/2 hour before I could go again. Morris walked back up the hill to see if I was alright. He was the old man of the fleet and knew about runaways. He said that as long as the front end was vibrating, I had a good chance of making it, if I could keep it on the road. Once it went past the vibration stage, continuing to pick up speed and starting to smooth out again, just say your prayers and wait for the end, because the wheels would be flying off, and possibly the running gear exploding apart at any second.
All this is happening, with no maxi brakes or power steering, to help control the situation. Old style bias tires would not help anything either. That was the last time I ever kicked any truck out of gear. You don't press your luck a second time.
END PART 6 ---
Just an afterthought, --- When I die, I want to die like my grandmother, who died peacefully in her sleep. Not screaming like all the passengers in her car.
-------------------- William (Diesel Gypsy) Weatherstone. RETURN TO STORY MENU