Does the vibration act the same in both directions of vibration lever movement? It could be an issue with the eccentric weight assembly or bearings. As stated you can pull the motor back and see if the motor is turning when stroking the lever and try rotating the shaft to the weights. The hydraulics are just Sundstrand/Sauer/Danfoss. You can find manuals on the Danfoss website. Vibe pump should be a 46 series, motor it depends on what variant you have. Propulsion are 20 series.