day cab back glass

That happens when the glad hand slapps it because it wasn't disconnected while unhooking. Even if it doesn't break immediately, it wi weaken the glass to where a few temperature cycles will finish it off.

 

I used to have rocks shatter them. Pulled a drop deck flat, and one tire was exposed. Told the company what was happening, needed fenders installed.

Got a blank stare, and told "too much money". So replace the back glass twice a year, and you would have paid for the fenders.....

 

Or put a headache rack with chicken wire on the jail window...

 

Check to make sure your seat isn't putting pressure on it.

Had a driver break the back glass in a box truck that way.