I recently did this hole-drilling modification when changing the transmission fluid in my 2001 2.7 / 5-speed. I found it so much easier than removing that huge structural/transmission cooling baffle plate!
Location where I drilled mine was 18mm to left (and a little bit foreward) of the pictured reference hole for this 2001 5-speed:
...it ended up coming out "spot-on", but I imagine the 6-speed (and possibly even the early 5-speed) may require a different hole location):
One thing I struggled with was removing the filler plug without going to dramatic measures, like putting the car on a lift. I found it's accessible leaving vehicle on the ground, by using the following tool setup: (17mm hex bit driver, universal joint, socket extension, and large 1/2"-drive breaker bar)...
...and accessing it from behind the left rear wheel (although one detail not visible in the below photo is the socket extension reaches across
in front of the half-shaft):
I was unable to remove the plug when engine was cold, (even with the huge breaker bar!) but getting the driveline up to full operating temperature did the trick for allowing the plug to break free. (Also the hot transmission temperature when draining also helped that fluid come roaring out of there!)
When the fluid came out, it kind of made a mess as the fluid seemed to drain out in various sideways directions. If doing it over, I'd use the milk container funnel shown in the 3rd picture of the original post of this thread. I personally feel that the 2" hole I drilled is plenty big for this.
I fashioned an 11mm "dipstick" out of a paperclip, and used it through the filler port to set the fluid level, as suggested in the 101 projects book, and got lucky with not having much problem filling to the correct amount. I pumped fluid up from below. Initially pumping fluid in with the rear of the car jacked up a bit, until it overflowed (then lowering to flat on the ground), put the level very close to perfect.
Bottom line: the improvement in reduced shift effort with this service work is huge! I'd say subjectively, there is only 20-25% of the effort in getting into gears as there was before! I can feel the difference in most operating conditions, hot and cold, although it's most noticeable in 1st-3rd gears and most needed when very cold, but nice improvement even warmed up. I find myself "rowing the gears" more now, and not coasting in neutral, or skipping over gears as much as I used to with this car. Heel-and-toe is more effortless, enjoyable and reliable, as is double-clutch downshifting!!
The car has about 120k miles on it, and I have no idea if the old fluid was original, or had ever been replaced. I used the special 5-speed genuine Porsche fluid, part number 000-043-304-71, sourced in 1-qt bottles from Sunset Porsche. It took less fluid than I was expecting... not even 2 quart bottles, although the repackaged quart-sized bottles Sunset provided were filled abnormally high. I was surprised that I didn't need to even crack open a 3rd bottle which I also had ready to go...
