I drove a big gas powered rental truck pulling a big trailer, from San Diego to Tampa and, exchanged the sludge in the oil pan for new oil and filter, changed the air cleaner and both fuel filters. I discovered the maintenance issues after loading the truck and did not want to unload it to exchange it for another vehicle. I also draind out a lot of coolant that looked like sludge, and added a 50/50 mix of new coolant and distilled water and had to add air to every tire on the truck, including the spare, topped off the p/s fluid, checked the transmission and rear end. The trip went without a hitch and at the other end, they paid all my receipts without any questions. After loading the truck I just did not want to get stuck somewhere for somthing I could have avoided, and I can't stand the idea of letting these kinds of things go. Someone somewhere in the company did take notice, because, a couple of weeks later I received a letter with a voucher toward my next rental. I'll bet there are others like me, but many more that would never have lifted the hood or checked the tires.