have worked on many a vh4d but not vg4d, but here are some basics.
you should have a rod from the top hole in govenor to the carbuertor. a spring is normaly used in one of the lower hole to the throttle linkage or wire. if you have a rod from carb to gov. and start engine you should be able to...
buy your parts and service manual by s/n only. the frame, drive train and engines are basicly the same for all 763, the hydraulics and electrical are diferant. triangular head lights it's a g series.
all s/n are same way. left side screws onto fitting on hydraulic tank. so you have to drain tank or be quick and remove filter and cap with a #6 jic cap. right side screws onto same style fitting of hst motor. you can either by filter complete or just the bronze filter and orings they come in a...
kubota rings run about 70-80 dollars a set there should be a rebuild kit avalibal i did see something on ebay for a kit i'll see if i can find it for you.
you can always search the web for parts sources. perkins is a popular engine. you may also get them at a local parts source napa for instance. don't count out dealer on priceing also.
when you have engine out check u-joints and splines. before removeing check for leaks as with the engine out its...
look inside rear of the cavity where injection pump sits, you should see a small spring sticking out of the block. on the outside of block there should be a tamper proof cap covering a set screw. thr spring goes inside. caution do not mess with the adjustment for this spring.
fyi if you are running a vane pump hope you left the shaft loose if you tightened it up and then slid coupler on it will fail. the front fitting in the port block has a charge bypass valve under it if it is damaged or there is something holding it open ie a piece of metal it will cause problems...