One thing about tranny flushing is I would keep that to just transmission shops or actual dealers. So much can go wrong with a flush, specially if its just some stop and lube place I wouldn't have them touch my Hoe with a 10' pole. They barely can handle doing a oil change let alone do anything else right.
I've had nothing but nightmares with lube shops...Took my 91 5.0, has NO- Cats, smog pump, slammed to the ground with a Griggs Pro-Challenge racing suspension. I was out of town with the car and needed to make a 1000 miles run across the good ol' USA and wanted to have the oil changed, So I was forced to goto a lube shop...What a joke...first of all this car is so far past street legal it's not even funny, so I'm sitting in there making sure they put in Valvaline Synthetic and not Pensoil, and this joker comes in and says I need wiper blades and my serpentine was getting worn out, and my tranny is low on fluid. I said, your so full of shit it's not even funny...I said first of all the car doesn't even have wipers on it, Secondly...that belt is brand new, and I'd love to see them firgure out which one it is, took me two weeks to cross reference which one belonged on it since I've moved and rearranged the assessories, Thirdly...that tranny's not low, its a Tremec 3550 TKO and you dont just fill it to the hole...I told the guy, change the f-n oil so I can get out of this joke of a place...