Fallon
Super Member
I had a few finger sized holes in my tape job holding the vacuum onto my Grand L. If your vent is smaller than 1 finger (almost guaranteed) the shop vac will still pull enough vacuum to prevent a leak. The combo fill port & vent is convenient in thoery. But has no lip or hose to stick the vacuum nozzle over. Your only option is a 2nd person or taping the nozzle to a flat dirty surface. Less of an issue if the car is on & trying to suck itself to the transmission. But that might come loose as the vacuum decreases when you open the filter or drain at the bottom.Are you thinking to leave an air gap at the fill port, where the shop vac hose would be? Or to leave the breather vents open? Where are those on a Kioti DK40 SE if you happen to know?
Fun science project for kids or enquiring minds... take a 5 gallon bucket with a lid. Put a drain plug sized hole in the bottom & fill it with water (plug the hole with tape or a finger or something). Hook up a shop vac to the pour spout on the lid. Turn the vac on & unplug the hole at the bottom. Start cutting a bigger & bigger 2nd hole in the lid. I'm guessing you could get to a dime sized hole before the bottom one starts leaking with most shop vacs.
1 square foot or so (guess for bucket upening) is 144 square inches. Times 0.1psi (guess) gives you 14.4 pounds of force pushing up through that hole in the bottom. More vacuum gives you a lot more force. More than a psi or 2 of vacuum would crush your bucket, or seals on your transmission, so it's good a shop vac won't get much actual vacuum.
Fun science teacher experiment. Tell your class anybody who can suck water up a straw/hose over 32' can skip class for the rest of the year. Absolute vacuum won't support more than a 30' water column or something like that (varies on altitude & air pressure as well). An nobody can suck that hard anyway much less get a real vacuum pump to do it.