My 6620 TLS has always vibrated at bit a certain speeds on the road (circa 20kph) not badly but enough so that I thought I better check the UJs and shafts under the tractor. There is movement on the shaft but it isn't in the UJs I think its in the "self aligning bushing" and bearing where there are 2 grease nipples fitted. If you take the weight of the front of the tractor you can move the axle ever so slightly back and forth. I have received advice to replace bush and bearing and some capscrews in there from someone familiar with these tractors. Anybody else come across this? Presumably needs sorting before it gets any worse? Anything else we need to look at when we are in there? I'll tag the usual suspects @Phil P @Timbo @Tractortech