awdinut

I think I need the 'blue fluid fix' for my 04 tranny...ocaisional hooting, occaisional slip/stutter/shudder type event on take off, and a bit of a clunk on the 2nd to 1st down shift. That would cost $2K. Part of that fix is a re-flash of software. I know of two Phaeton owners who had the re-flash done but did not change fluid and in both cases the tranny problems were solved. One of the Phaetons is owned by a VW Phaeton tech. He put the blue fluid in after 30 days of driving on the re-flashed tranny because warranty was paying the cost but he said the fluid made no difference at all.

Any A8 owners tried just the re-flash? The cost would only be about $100, so it would seem to be worth trying before droping big bucks. The Phaeton that never got the fluid change has gone 30K miles since, so the experiment has quite a bit of 'annecdotal' evidence to support the theory.

Brozee

That's odd that just a software change would solve the small shudder and hooting noise I got before I did that exact same service. And the cost was 2k. Not sure I doubt it would work, because I actually felt it and I don't know how a simple software change would fix it. Check into it a bit more, wouldn't hurt because even if it doesn't work then at least you did the update to prepare for the fluid flush.

FlyTyinFool

A re-flash can solve similar issues with other manufacturers. I know for a fact that Chrysler has at least one model where a tranny shudder was solved this way. I don't remember which model it was. It wasn't the minivans. Chrysler had ongoing issues with their A604 4-speed tranny in the minivans, but that was a different issue a long time ago. The flash involved a more positive (aggressive) engagement on up-shift. The flash reduced the (intentional) slippage between shifts. I think it may have been the Sebring, but I could be all wet on that...
Way back in the day, I would install shift kits in my American muscle cars. B&M was (and may still be) a very popular source for the kits. You could install one of three levels of "stiffness" for the up-shift. The third level was just for the quarter mile. Way too much for every day driving.
Anyway, a tranny re-flash can accomplish the same thing electronically that the shift kits did mechanically. A more positive engagement on up-shift is actually a good because the clutches don't wear as much as they would with a "gooshy" shift pattern, because they aren't slipping as much to soften the up-shift. Less slippage also reduces the potential for shudder for the same reason.
I say go for it! You already know how much coin it's going to take to do the full meal deal, so why not attempt something that's $1900 less?
If it doesn't work, then you'll know with certainty that you have to drop the rest of the change on the full service.
If it does work then you can report that victory right here in this forum and possibly save a lot of people some pretty big money.

Best of luck! And, be sure to let us know, whatever you decide.