TO35 Hydrolic 3pt hitch

We are trying to get the 3pt hitch to raise and lower when we bought it the hitch was stuck at a bout half way, there was a lot of water in the gear lube so we drained it and added new gearlube, so that good now, after running the tractor for a while it started to jump around when ever the clutch was released and the arms started to raise slowly, give it gas and it raises faster, put the clutch in and it slowly drops back down,

Know the issue we have is that as we drive the hitch goes all the way up and its not to useful for cutting grass

any ideas on this issue.. more info about tractor below

the previous owner by passed the up/down/draft controls to the right of the seat, inside the gear casing the two fingers that operate the pump have been tie-wrapped together and on of the bolts in the side dipstick cover has been truned into alever that pushes the pumps arm with the roller to the front. when the up/down control is set to up it allows the 2 tie-wraped fingers to move toward the front and then they spring back and move the pump arm and addon lever move towards the back of the tractor.

Now in playing with the lever moving the roller arm of the pump back and forth it makes no difference in the operation, it still raises when clutch is released and lowers when the clutch pressed. If I buy the complte top for the gear case that has all the linkage and fingers will this solve my issue, or perhaps if I remove the tie-wraps from the fingers the issue will resolve itself, I'm trying to avoid buying the whoile top piece, I've priced it at about CAN$400 and I don't really want to spend anymore then needed