hi everyone, i have a 2000 nissan xterra XE 4X4 with 63,000 miles and have this rattling noise coming from underneath the car when accelerating. At about 40,000 miles it had the same problem and the dealer corrected it by removing this rusted clamp attached to a heat shield. the noise has appeared again and again i took it to the dealership, now at 63,000 miles. again a technician went under the car and removed another rusted clamp securing a heat shield, informing me that there are still 2 clamps that hold the heat shields in place. this did not solve the problem. what the service ppl told me was that i can either a) remove the 2 remaining clamps(which are rusted shut) and take the heat shields off for about $40 to $50, or b) replace the entire section of piping and heat shields for an estimated cost of $400-600. my question is is it safe to remove these heat shields from the drive train? can i go out and buy some clamps at a local hardware store to replace the 2 clamps that have been removed and the 2 clamps that are still on the drivetrain? is it common for these clamps to rust through and will nissan possibly cover this under the corrosion part of their warranty? thanks for your time.