Agree you have a venting problem, relatively common.
Vent may be hard tube screwed in or perhaps more likely a black rubber goose-neck like question mark stuck onto a nipple.
Mine has three--one on each axle side and one built into hydraulic filler cap.
Doesn't take much to vent: I got tired of dirt daubers (mud wasps) and used a short piece of fuel hose and shorter piece of copper tubing mashed almost flat in vise. Vents but without bug intrusion. Have also seen rags or old sock tied over vent.
Please post back your continuing experiences so we may all learn.