Sqeaky when towing

[dallasrules]

I have a 2004 cedar creek 5th wheel. 33', around 13k max weight and 3 slides.
When I tow it, it is very dweaky.. i don't know particularly where, but it's very noticeable with mt windows down. I haven't had this problem with any of my other trailers and it is totally out of my range of knowledge

Can anyone give me ideas of thing to check? I know I am vague, but the 2hole thing just squaks.

It tows fine and straight even at around 75mph.

Also I didn't mention we use an andrrson ultimate hitch, but we use that with all our 5th wheels without issue.