Hi all I'm new here. We just got our 2002 Pathy SE 2 weeks ago. It's a 5-speed with 100K miles and it looks real nice. When we test drove it, there was a rattle from the back that sounds like loose heat shields. No problem, or so I thought.

But...

I checked all the shields and they are all solid.

The rattle only happens between 1500 and 2000 RPM and is most pronounced in 3rd gear and above.

In 4WD it is about half as loud, but still there.

I replaced the 4 control arms and put in all new fluids everywhere. The fluids came out dirty but there were no chunks on the drain plug magnets. The exhaust system was replaced in the last year. No pipes are touching any frame parts. The shocks are rusty but don't leak.

In trying to analyze the situation, it seems to be rear axle related because of the noise difference between 2WD and 4WD, but what in or around the axle would make that sheet metal sound?

So I've run out of ideas. If anyone has cured such a mystery rattle, here's your chance to pay it forward!

The mechanical difference between 2wd and 4wd is in the front of the car. Everything in the rear remains unchanged. Take a good close look at the shocks again, particularly the bushings. When the rubber wears out you get a metal to metal noise. That could be what you're hearing.

Hooligan wrote:The mechanical difference between 2wd and 4wd is in the front of the car. Everything in the rear remains unchanged. Take a good close look at the shocks again, particularly the bushings. When the rubber wears out you get a metal to metal noise. That could be what you're hearing.

Hooligan, I think the difference is that in 4wd the rear axle gets half the amount of torque, where in 2wd it gets 100%. I don't know why that would make the noise different though. The shock bushings are intact and flexible - no metal touching. The noise/vibration seems more related to low engine RPM than anything else.

I'd just like to know that its not a bad bearing or something in the transfer case or differential.

I had a rattle in the rear end one time that I was convinced was muffler related. I was under that truck at least a half dozen times shaking everything in sight. I was even going to replace the rubber hangers.
It turned out to be a broken spring. It was broken near the end of the coil so, there was no appreciable sag in the rear of the vehicle. The plastic cover on the end of the spring held the broken piece of metal in place so, there was plenty of metal to metal contact. Do you get any increase in noise when on rough terrain or is it strictly rpm related?

If I bang on the muffler there is a slight rattling sound. However when its idling or revving and I listen below its as quiet as can be. There is no suspension clanging or noise when going over bumps and such.

I'm thinking now there's a loose baffle in the muffler that's vibrating under certain conditions, but its far from certain. Baffling baffles.