As far as I am concerned..redline is the best stuff for your trans (next to
shifting slowly) that you can do for longevity and making it last longer. The
units I rebuild that have had redline in em are cleaner,less bearing wear,
AND the pinion teeth are LESS worn....Those of you that haven't changed your
gear lube in the last 30K should do it.
I see no more leakages as a result either. Its a no lose situation once you
get it in there...Just my humble (professional) opinion. I see 25 +  VW
transmissions per month so I should get a fair cross section.
Daryl of AA Transaxle