2000 jetta Drivetrain problem, ????

My 2000 jetta has been making a loud knocking noise from the front-end, its loudest in 1st and 2nd on take off, but is heard throughout all gears. it stops or at least gets quiet, when i push in the clutch! Do you think my tranny could be going at 80,000. It shifts perfectly and I have all gears. Is there any common drivetrain problems with the mk4 jettas, the sound has come and gone just recently, since I noticed it yesterday, wouldnt a tranny problem always make a noise??