Hi,

Sorry for the delay but i've been away for a while!

Its hard to tell with these type of problems without seeing the machine due to the vast array of possibilities but I would say you are on the right track for starters. Trouble is you have a Hydro system to take in to consideration as well....

The Hydro Pump is belt driven, the juddering and vibration could be down to a week tensioner pulley / spring causing the pulley to bouce erratically when under load. Locate the pulleys + springs and walk along side the machine while someone drives it up the incline to force the problem and watch for this happening.

Secondly it could be the Hydro pump itself. If the seals are starting to go internaly it would drive fine until either the unit / fluid gets warm or the hydro unit gets put under increased load (like pulling up a hill). Which would also be a good indication of why it was sold in the first place! Check at the rear of the machine for the Hydro Fluid reservoir and make sure theres the right amount of fluid in there for starters and let me know what you've found.

If you need any Honda spare parts check out www.jungle-busters.co.uk and if the parts you need are not listed you will need to call them on 0191 4692020 along with the chassis number to ensure you are getting the right parts sent out for your model of tractor.

Hope this helps