Larry,

Have you inspected the bearings in your original alternator?

My bearings went out on my Chevy Van at 145K miles even though the regualtor was fine. I replaced the entire unit since I felt I got my $ worth with it lasting 145K miles.

Its easy to overlook the mechanicals on an "electronic" part.

__________________
Ray
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles