I have a 2004 VW GTI VR6 with the 6 speed manual, and I have just developed a tap in the transmission. It only occurs in a very specific situation- the transmission must be in gear, foot off the gas, just a very light coast. The engine will usually be around 1000 RPM, between about 25-30 mph. Basically, the transmission must be in gear with no power going through it, either to or from the wheels. I have already taken all the wheels off to see if there is any visible problem, but everything looks pretty good. If you have any ideas, please let me know.