We bought a K430 new in 2010 and last month it started doing the exact same judder when you flick the shuttle with the PTO running, dealer has had it on dyno and found nothing. This comes after a gearbox rebuild after a bearing collapse in March this year. It has been a very unreliable tractor thus far with various 'niggly bits' some bigger than other, if this continues i can't see it being with us for much longer. This is our third Deutz since year 2000 and is the only one weve had real issues with, if you ask me id say its the poor italian build quality. Please let me know if you find what the judder is caused by, or if yours goes bang before mine.