Tyler Tuesday: Trucks, Trucks, and More Trucks

There are many types of trucks that I work on here in the big city of Dallas. There are the day-cab delivery trucks, which locally move loads of pallets, equipment, boxes and supplies and are happily parked in the same yard every night. There are the line-haul trucks, moving things around the country and crossing state lines as one would cross from the living room into the kitchen. They are larger with extended cabins to sleep in and have heavier components to handle the weight. And then there are the tough vocational trucks. These are the trucks that every little boy wants to crawl all over: sit in the seat, play with all the switches, and marvel at the huge tires, long chassis, and low growling idle. The bulldog brand Mack Truck is known for making tough vocational type trucks. 

This was due to the type of engines they made early on to go with the outstanding Maxitorque transmission and revolutionizing camel back suspension. While other truck brands were making their engines larger, Cummins producing one of the first 15L engines (the ISX series) and Caterpillar following suit with the C15, they could not keep up with Mack in the off-road world. These large engines of the competitors almost killed themselves trying to rev up and down all day tearing at the mess of hot pipes and pounding pistons. If you know a little about engines, the larger the displacement of the cylinder, the slower the speed of the engine. Mack was producing engine around 9 to 11 liters and found a different way to make power: through the transmission.  Driving larger engines in an off-road situation was like trying to drive a race car in a shopping mall parking lot. Every time you let the clutch out enough to start moving, you have to slam on the brakes to stop from going through a parked car.

Trucks can be powered by large engines or by small engines which turn more gears. I had written out an entire paragraph about how power is made and why transmissions can distribute power over smaller rpm bands, but I decided it was very boring/confusing. So just trust me when I say Mack had a better application for off-road vehicles by using slightly smaller engines and heavier duty transmissions. This was combined with a genesis suspension system that I could go on and on about but basically the idea is that when one axle goes up it forces pressure on the other to go down, so that you never loose traction. 

What I was faced with on the truck yard was one of these trucks. Mack thoroughbred, heavy duty, extreme killer of a truck. 

It’s called a cement pump truck, and it takes large amounts of cement and pumps it into foundations or second stories of buildings - or anywhere within its mass arms’ reach. This truck had a code active that only let it rev up to about half of its capability. As I started the fault tracking, it took about two hours to find that I needed to repair wiring on top of the transmission. The transmission, I discovered, had been involved in an accident. And not just any accident: an accident where the people using this truck dropped a bunch of cement on top of the transmission. It probably looked like an insignificant amount compared to what was being pumped elsewhere, but trust me when I say that it was enough to make my job very hard.

I spent the next four hours chiseling cement with an air hammer while stooping halfway between the body and the top of the transmission. The hardest part was making sure that I chiseled only cement and not truck parts. Even then, I couldn’t help but think it was one of the coolest jobs I had ever done. I was smiling the whole time.

How awesome is it that I get to work on cement-covered pump trucks and top-of-the-line highway trucks all in the same place? I truly am grateful for such an awesome job. 

One last note, if you think that driving a truck like that is hard, you should talk to the tow-truck driver who brought it in. He was driving a truck just as long with the cement truck behind it! That takes some serious driving skill!!

Currently listening to: Bon Iver, Foo fighters, and U2. Where did that album come from?

Currently working on: Volvo VNL64T EGR valve is stuck open and needs to be replaced. 

Currently thinking about: Swimming, biking, and running.