For the guys or ladies that have mud flaps installed on your Tahoe. Do you get a lot less spray on your hatch window then without them?

 

Maybe a little bit less but they do help keep the sides of the truck cleaner.

 

A rear "down" spoiler mounted above on the roof will create airflow at speed to help blow the spray away from the rear hatch.
When at speed there is a vacuum created there sucking everything into it as you drive.
Some stuff sticks and some stuff don't.

 

Thanks for the info, I'll check out the spoiler idea