I've used air shocks on my trucks for years. Why aren't they available for a 2002 f50 4wd
Unless you just have to have OEM equipment there are several available. Try this place. They list several. http://www.autoanything.com/suspension-systems/10A50469.aspx
Search Ford F-150 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford F-150 Experts