Make sure the shovels are in good shape & not worn out. I had bought a seven shank cultivator-Deere. It had worn shovels. I could pull it about 5 mph in dry hard ground doing food plots. With more moisture, I would have to slow down to 3 mph, but it was no load for my 40 hp tractor. I had even thought about adding a couple of shanks. Last spring I put on new shovels, headed to the field, expecting to see how deep it would go at 3 mph. I dropped the 3 pt lever all the way down & came to a sudden halt. I had to use the lever stops to keep it from going too deep. By the time I got done tilling up 7 food plots, I was pulling up tree roots from when the fields were cleared 25 yrs ago & farmed each year until 15 years ago. No way could I add any more shanks now. On soil that has not been tilled for over 20 years I could let the control all the way down, but the second trip over it, I had to use the depth stops even with extra weight in the loader bucket-4wd.