as a driver that can do proper maintenance on these vehicles, I'll offer my services to change the oil, brake lining, fluid changes... for a much lower cost than what any shop charges.
I did a simple oil/ filter change on a standard cargo van for only $10 labor + costs of supplies. Internet resources are pretty much spot-on for the GMC / Ford vans.... and since the contractor was my regular boss at the time, he told me I'm allowed to bring it home. Heck, I clean the inside of the van anyways since I like to be neat.
I also change out the wiper blades and any burnt bulbs at no charge; just the cost of the part since my contractor had treated me good in the past <shrugs>
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@ your terminal, pool some resources/network with other contractors... some have formed together for fleet maintenance/repair with a few outside companies at a substantial discount.
Express should share some of their networks of service personnel that works on their vehicles to see who are interested in also working on Ground/ HD vehicles as well; only makes sense but this company can't even comprehend this suggestion
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as for your sprinter, lots of online forums for that
The Unofficial Resource For Sprinter Van Enthusiasts
that's a good site to research that vehicle; I remember the local mechanic had overfilled the crankcase because he was using older sprinter specs... I brought it to the attention of the contractor & told him that'll ruin the bearings if left that way! we drained some out, verified the level on the dipstick & moved on with our day.