Last time I changed my trans fluid on my 2003 f-550 torque shift automatic tranny. I drained fluid, dropped the pan, replaced internal and external filters, and refilled with Mercron sp fluid. Unfortionally I didn't measure how much fluid came out and I don't remember how much I refilled it with (I just checked the dipstick with the engine hot after refill and added more fluid to reach the full mark). Well now it's almost due for another change, does anyone know if when a dealer flushes a transmission are they going to use a Wynn transmission flush tool? Will that machine always finish a flush with the right amount?

 

Usually yes to the first question, and Almost always to the second question. You can call the dealership and ask them what kind of flush they do (a direct 1 to 1 means they use a machine, or they'll just tell you they use one) and any tech worth their salt will definitely set the fluid level when the flush is done. If you tow with this a lot or haul heavy loads with it, you might ask they set the fluid level to the lower end of full when hot, as the fluid will expand and 'breath' a good bit when hot.
One other nice thing about the flush is that the machine is flushed out after each use, so there's no cross-contamination of fluids from trans to trans.