I have a 2001 4.4 with 140,000 miles on it. So I'd say your good for at least another 100,000. At the rate your putting miles on yours (58K in 7 years) you'll probably be able to get "Classic Car" tags before you ready to turn her in (21 years 174K).

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2007 Suzuki Vinson 500 4X4
2007 Toro 6.5hp
2006 BMW X5 4.4 ltr (his)
2001 BMW X5 4.4 ltr (hers)
1994 Honda XR650L
1984 Honda XR80

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Benjamin Franklin