Ike....if you're mechanically inclined, why don't you just open it up to verify if you have sludge or not.

Moreso, are you the original owner or is this is used. Maint. records ?

The ONLY product I would recommend is www.auto-rx.com but beforeso, I would probably lean on opening it up myself to see how dirty it is.....or decide yourself based on past service maintainence.