Edit: I looked it up. For Q1 2017, their parts + service generated 72% of the companies gross margin (or $38.5 million). 

Having lived through the 80's, being an implement dealer, the dealers that survived generated 100% of their gross margins, from parts and service sales.  Just raising the price of parts and labor rates, will drive customers away to other parts vendors and "shade tree" mechanics.  This means a lot of hard work in the implement dealerships, to keep parts prices competitive and shop labor in line with other local non-dealership mechanics.