The key is making sure the collar under the ball is tight after you insert the ball and lock it in. Should have a bar that clips to the handle, which goes into the slots on the collar.
The trailer is about 4500 lbs and the driveway is mostly level with a small, short incline up onto the parking pad. The company website has guidelines for which models can handle what weight on what grades. parkit360.ca.
Can you possibly send me a picture of how you switch it out of neutral and how to put it in gear. I’m not sure mine has 2 different speeds either. My boyfriend is the one using it to park my 2800 lb horse trailer. He seems to have a lot of problems with it. It doesn’t work for him as easily as you are doing it and I don’t think he is using it correctly.
I don't think we can send photos in this comment area. On the left side of the unit, just behind the tire, there is a clutch. It's a circular piece of plastic about 3 inches in diameter with an indicator arrow on it. You just rotate it one direction to engage the gears, and rotate it the other direction to free-wheel. It's a standard winch clutch. You can google up pictures of winches and see how that works. You have a different model if yours does not have two speeds. So the clutch might work differently on yours.
