tracker/merc tilt

my son has a 99 merc 115 with a single tilt cylinder, the problem is when you let the motor down it makes a squeal, you can spray the shaft with a little wd40 and it will stop but after a few minutes it starts again, seems to work the way it should and is not low on fluid. any thoughts?

WD40 isn't much of a lubricant. The WD means "Water Displacing", and that's what it was designed for. Use some spray white lithium grease or just dab some marine grease on there and see if that lasts better.