Once again, the 18" Venture actuator is one of those junk Chinese Superjack / qarl clones. It's NOT made by Venture, it's imported by them. It's complete and total junk. I don't understand why they still sell it, as it turns their reputation into junk.
I love Venture actuators, the 18" one sold by them is NOT Venture made, and people should NOT buy them. The 24" model is good, and the 24" BALL-SCREW model can go the rest of your life with no issues. Yes, it's a little pricey, but it's worth it to not have the frustration.