'95 Cherokee - "Clunk" Coming From The Rear End

[FallenZen]

Okay, I have a potentially serious problem. A new sound became apparent today in my 95 Cherokee.

Symptoms:
1) On engine ignition a series of rapid "clunk" noises are heard.
2) When the engine is turned off, a series of rapid "clunk" noises are heard that are identical to the ones heard on ignition.
3) When driving down the road, bumps that shake the car in a front-to-back style motion seem to result in a clunk or two. It is much less frequent with side-to-side bumping. Rocking the Jeep does not produce the sound, only bumps.

It sounds like something is loose. I've traced the sound to its general vicinity and it comes from the rear of the Jeep - it sounds like it's coming from under the steel plate I have covering my gas tank. Whether it truly is or not is another story.

I'm very worried that it's transmission oriented due to the ignition / de-ignition symptoms. The clunk does not occur when I shift gears although if I'm on a slope and I shift from neutral to Drive it does result in a clunk. Being in 2 wheel drive or 4 wheel drive seems to make no difference.

Does anyone have any help for me? It's rather imperative that I get this sorted as quickly as possible, and if I can fix it myself I really need to. I don't have much money to spare, but this is a priority fix for me.

Thanks, in advance, for your time and help.

-Zen

[FallenZen]

Okay, well I've identified the problem and I thought I might post it just so nobody wastes their time thinking on it.

The thing (I really hate it when I forget what things are called.. Damned CRS) that bolts the exhaust pipe to the frame rusted through and the pipe is getting bounced against the gas tank. [insert great sigh of relief here]

I'm getting a welder on monday and I'll have it fixed then.

-Zen