I have a 753 and what I can read of the serial is something like 5127182... It is hard to read being extremely weathered. The person I bought it from had the Dealer do a lot of work and they told him it needed a new control valve. He didn't want to put any more money into it so I bought it. The only problem that I have found so far is the Bucket won't tilt back, unless you turn on the Aux. and push the left Aux switch. Looking at it, there is a Lock Valve (not sure of the proper name of it) in line with only one side of the bucket cylinder, located right under the hydraulic tank on the wall. I have tried both of the plugs that were originally pluged into the Aux. solenoids on the control valve and that didn't work. The only other solenoid plug that I can find is in the back by the Hydraulic Filter, which has an Orange and Black wire going to it, and has power when running. Could this be the connector that should go to the valve?