On my TJ, you here a metallic rattling sound. It seems to be coming from underneath the car behind the engine. Especially if you put a bit of a load on it.

I put my car into D or R you'll notice the sound, especially when you put the engine under load or have the handbrake up. When I rev it slightly but sharply when its in P or N, the sound is less noticable. It seems to be louder when there is more load on the engine, especially when accelerating.

Is it something to do with the exhaust near the engine, maybe perhaps getting extractors will fix this problem?

My car has the 6G74 engine of course. It had its timing belt changed about 10,000kms ago. Has tiptronic auto, 5 speed.

TJ? Mine as well. Goes away when it warms up. Rumour has it that there is a divider inside the "Y" joint of the exhaust that lets go of its spot welds and rattles around. It will probably rust away eventually, but extractors would fix it if you pull the offending bit of metal out when you install them.

Or you could just get the offending piece chopped out.

Mine was the catalytic converter... Half of it had disintegrated inside.

I may or may not have applied the obvious solution...

If the rattle is there all the time is is more likely to be the cat con, I would think.

Okay, well its not affecting the performance of my car or anything and its probably the Y joint. Just the noise a bit annoying. And yes its slightly worse when cold, but even when hot it still makes the noise. Apart from that the car drives very nicely. Just to let you know my car is a Sports, its pretty much stock apart from aftermarket rims, tinted windows, aftermarket cd player/speakers, the usual things.

Generally if its your cat you will succumb to some sort of change in performance.

Most of the time is the splitter in the engine pipe, you can get it removed but then the performance of the engine pipe may suffer, I have in the past opened them up and re welded the bit back in but usually I just pop on another second hand pipe

Maybe a long shot, but I had a rattly sound coming from what I thought was the Y join, and no loss in performance, ended up being when I turned the A/C off it went away and came back when I turned it back on. So could be A/C belt pulley rattling away.
Like I said, a long shot.

Maybe a long shot, but I had a rattly sound coming from what I thought was the Y join, and no loss in performance, ended up being when I turned the A/C off it went away and came back when I turned it back on. So could be A/C belt pulley rattling away.
Like I said, a long shot.

Nothing to do with the A/C.

Maybe I'll look at a complete exhaust replacement, front to rear sometime in the future. Any websites out there that sell complete exhausts?

I have the same problem, the exhaust shop told me it's the Y pipe and quoted me $150 to weld that rattling pipes.
I bought these extractors instead and wrapped it to reduce the heat in my engine bay especially this summer season.
http://i122.photobucket.com/albums/o248/MagnaTech07/Exhaust/extractor.jpg

ive had the same problem as you have mentioned and it turned out to be the exhaust diverter in the y joiner, no power loss just embarrassing , it ended up costing me $250 to fix and i can honestly say i didn't notice a power loss.

My TJ had the same problem too a few years back, I got it rewelded, cost a couple of hundred and then a year or so ago I found a hole in the exhaust up by the manifold. I got a quote, another couple of hundred to fix and they might not have been fixable so it might have been more $$. So I thought I would just get some extractors off ebay, cost $450 for supposedly stainless steel and made by the guys who made them for the VRX or ralliart. The fit was good and they weren't too hard to fit but short story is these too have now got the dreaded rattle. They do have a warranty but I really can't be stuffed going through the hassle to sort out the warranty or getting them welded also as it's now just the work car.
I don't know what the worse thing that could happen is, it might just be an annoying noise or potentially the divider could come away and end up in the cat?

http://www.youtube.com/watch?v=bEG2oyblLgA

http://www.youtube.com/watch?v=bEG2oyblLgA

Yeah, most of us know what it sounds like! lol

Yeah, the noise is louder when cold. But once you drive the car the noise is much quieter after about 5 minutes. What needs to be done, cat convertor?, Y section? I'll probably get extractors when the time comes.

Driving my TJ yesterday evening I got about 7 to 8L per 100kms driving between 70 and 90km/h on slightly hilly country road with fairly gentle driving. That's pretty good for a six. It was in D most of the time, but I find - and + useful for hilly roads so it doesn't shift into 5th all the time.

Regarding the Y joint and splitter, Is it possible to get under the car and unbolt/ fix it, or is it a weld job?