Drive with a faulty timing chain or replace.

What is your question?

My 2005 6 cal Ford Explorer Sport Trac with 200,000 miles on the clock,has been diagnosed with timing chain problems. I have been advised to replace all 4 chains. I have not seen any oil spills under the engine or on the floor nor heard any other noise apart from the timing chain rattle. The quote is + - $3000.

What makes this problem better or worse?

No

How long has your 2005 Ford Explorer Sport Trac had this problem?

A couple of weeks