Take the whole kicker off and you need to pull the top part of the kicker off with the bolt holding the 2 pieces together.
Be careful when you take it apart as there's a small spring and ball bearing in the lil hole.
What i do when mine did that is get some bearing grease and lube everything up nice, kicker shaft were the 2 pieces meet, the ball and the spring, also replace the o-ring at the bottom if its worn out.
There is rebuild kits for cheep also, that come with a new spring ball and o-ring, but lubing them up will be fine. The rebuild kits are if the ball bearing is not round or the spring is worn or broken.
Mine used to rattle ALOT also and what i did is go to the hardware store and pick up a small coil spring and cut it to size and stuck it vertically between the 2 pieces and bolted the 2 pieces together like you always would and its never rattled again. I Also stick 2 o-rings between the pieces also, works like a charm, never sticks in and never rattles again.