Kill the fixed-ops mailer. If your goal is to increase business to your fixed-ops services, I strongly suggest digital campaigns.
Even if you are slow in the department only a couple days a week (Tuesdays? Wednesdays?), tune your digital campaigns for fixed-ops to run for a shorter week and move to incentivize those slow days.
You have so much flexibility. Check out the DEP Toyota parts and service digital advertising case study to find out what may work best for your dealership.
Yago de Artaza Páramo