Hi Trroll…never used grease. This brings back memories when we were going to our first Eribameet 4 years ago and spent 2 hours driving round and round Chievely Services trying to work out the terrible noise!!. Eventually someone helped us and told us to wire brush the tow ball, then use a green scourer over it and finally wipe clean with a dry cloth. On the tow hitch part use fine wet/dry sandpaper and rub round inside the ‘cup’ to deglaze the friction pads and again wipe clean. We now do this everytime we hitch up and have never had the problem back. Good luck. Chris