I was told my transmission has a oil leak on the left side. This truck was just serviced and checked with tuneup, complete oil change, tires balanced without them acknowledging this oil leak? They changed the oil could this be something they didn’t do right? Or is this something that already been there they didn’t notice?
Or it didn’t start until after it left the service. 15 year old truck, leaks happen.
Nothing they previously serviced need them to touch the transmission. An oil change is not a transmission fluid change. I’d suggest you stop looking for a culprit to blame this on and just fix the leak. If it has never had a transmission fluid and filter change it is way overdue. If the truck has 4 wheel drive, have the transaxle fluid changed as well - and look for leaks on that, too…it is blue fluid.