Trim/Tilt motor "MAYDAY"

[Vix New Shoes]

I have a 1988, 21' Seaswirl, with a 5.0L 2barrel, OMC/COBRA. The Trim/Tilt motor works normal when raising the outdrive, but makes a cherping squeeling noise, as it is lowered. And will also make a slipping/thump of a noise when I troll at my slowest speeds (2.4>3.0 mph). It runs great at 35mph. I sure could use some help with my problem. Thanks, New Shoes