I noticed a "thrum" noise from 30-50 coming from the rear - possible wheel bearing. 98 SVT with 28k. Took it to the dealer for the heater resistor recall, paid them $25 to diagnose & advise. $250 total est, $120 for the part!! I called NAPA and got the part for $38. The manual & posts I've read make it sound like a fairly easy job. Any input?