Luvoffshore

My boat is a 97 with a 454/300 hp OMC and has power steering. When at no wake speed I hear the steering squeaking when turning back/forth. At the steering column, it has a long clear plastic tube off the side of the steering mechanism with a spring inside and a cap on the end of it. I assume this is where you fill this tube with something like marine axle grease and let the natural action of the use of the steering lubricate the length of the cable. It looks like it had grease in there at one time because it is a different color over a small length of the tube. I have service manuals, but there is nothing to say about what this is. I would call my boat dealer, but they are such butthead a _ _ holes I don’t even want to ask them. Give me your opinion if it is ok to fill this with grease.