Belt Or Gear Driven, How To Tell, And WHY?

Will be taking CDL test on Friday and fine tuning my pretrip inspection segment. Am still not sure how to tell and belt driven water pump/air compressor from a gear driven one. Also, why do I need to know this? Seems like the knowledge could help in diagnosing a cooling problem but could anyone shed some light here.

Gratefully, Gopher

It is important to know the difference so should you see a broken/missing belt, you know what it drives so if you are having issues (belt driven water pump) you know what to be looking for.

If it is toward the front of the engine (water pump as an example), chances are it is belt driven. If it is toward the rear of the engine (air compressor), chances are it is gear driven.

Also, the examiner what's to make sure you know what you are looking at/for of the major components on the truck/trailer/engine, their purpose, and you actually know what you are looking at/pointing to as you go through the pre-trip.

Hope this help to shed some light onto this for you.

What I did was pretrip as many DIFFERENT trucks as I could. Some had parts that were belt and some parts that were gear driven. I compared the 2004 truck with a belt driven air compressor to the 2006 truck who's air compressor is gear driven and I'd make a mental memory of the differences in how they looked. If your training yard has multiple trucks, pop the hoods open and just glance and compare.

That's what I did and it taught me well. If I had any confusion I talked with an instructor. They are there for you and should help you out.