IIRC a while back one of the forum members here posted instructions (with pics IIRC) how to make the TCC repair without removing the engine. Wonder if the repair worked permanently.Yes, PCNA must have a good reason for the time & trouble to remove engine to properly fix the TCC leak.
I am not a mechanic but, I am thinking they need to be able to access every single bolt & be able to remove cover, replace gasket & tighten all the bolts. Maybe they replace all of the TCC bolts, even the ones not broken or damaged? Maybe there is a new bolt with a new part #?
I suspect those dealers that do a much quicker repair, with engine in, by just replacing the broken bolt or bolts & do NOT remove cover & replace gasket & reseal are doing a temporary repair & hoping you either sell the car or are out of warranty by the time the leak reoccurs. Or maybe the new owner will not notice the new smaller leak.
If there was a way to leave the engine in place but, just remove enough parts to be able to fully access the TCC & do it correctly, why does Porsche not specify the this is the way to do the repair?