Universal joint broke

I had a chance to speak to a now retired diesel mechanic on this very issue late last night. What he said was most all parts have a wear cycle. If it moves it wears. One reason vehicle owners care about PMs is they help in finding things. I did not know this but some shops after changing oil will send a random sample to a lab to have the oil analyzed. There is normal wear and abnormal wear. A vehicle is expected to get so many miles on a set of brakes, oil, tires and things like a clutch. If they see abnormal wear and other vehicle's using same batch of parts is still running they will report it as driver abuse. MPG is another issue. I have seen computer printouts showing how MPH figures change based on a driver change. There is a proper way to operate a CMV and a wrong way. It is possible to rip a drive train out by a simple incorrect shift. I saw a guy learn this the hard way on I 20 near Monroe La about 10 years ago.

Many years ago on my Chevy S 10 I had a universal to start to go bad. I started noticing that there was a figure 8 motion in the things I could see in my rear view mirror. As @GasHauler said there are warning signs.