I'm one of those that frowns on drive through car washes.
I own, and use an MTM Undercarriage Cleaner to spray down the undersides of our daily's. The tool connects to my (gas powered) pressure washer and blasts the undersides of vehicles with four 45 degree nozzles.
https://adamspolishes.com/products/a...AaAmr2EALw_wcB