It's very simple! Contact your Service Guy, tell him you want a specific time for the Mechanic that WILL be working on the truck to look it over.
I did the above with my two leaks, the Mechanic put it on the lift and determined my timing cover to pan gasket needed to be resealed. He said most likely my trans rear seal was leaking but he told me he would get that seal and the front seal of the transfer case and replace BOTH no matter what he would find.
Made an appointment, got NICE loaner car. Very happy with the Service!!!