02 Silverado Exhaust Rattle

[Ol'Jim]

Happens at 1700-1900 RPM, during mild acceleration Sounds like all 8 connecting rods bearings are shot. Was guessing it was the heat shield on muffler/cat, but there are none. Finally got the nerve to lay under the truck while a buddy power-braked it to the point of rattling. Thought it might be the cat internals, but I grabbed a short piece of 2x4 and pressed it against different places along the exhaust system til it quieted the sound. Found the culprit, it looks like a bushing(?) in between a slip-joint near one of the cats. It is shaped like a short piece of pipe, like a sleeve that fills the gap between the 2 pipes. No idea where to go get it replaced, or if it can be done at home? Anyone have any idea what this thing is called? Anyone had one replaced? Cost?
Thanks, -Jim.

[slo99sierra]

Are you talking about the y-pipe that connects the two catalytic converters and ends at a flange?

Are your catalyric converters original or factory replacements? And pics would help to.

[ukrkoz]

2 cats? it has 2 cats? you sure it's not a cat and resonator?
i just went through the manual, it is referring to single cat only.

anyhow, are you referring to a flanged Y-pipe that connects both exhaust manifolds to exhaust pipe? there's a special heat resistant donut gasket inside the flange, that's a store item. if the Y-pipe went rotten and rattles,/leaks exhaust, it's either salvage yard or dealer. doubt you'll get it from a store.

[slo99sierra]

Originally Posted by ukrkoz

2 cats? it has 2 cats? you sure it's not a cat and resonator?
i just went through the manual, it is referring to single cat only.

anyhow, are you referring to a flanged Y-pipe that connects both exhaust manifolds to exhaust pipe? there's a special heat resistant donut gasket inside the flange, that's a store item. if the Y-pipe went rotten and rattles,/leaks exhaust, it's either salvage yard or dealer. doubt you'll get it from a store.

All 1999+ GM new body style fullsize trucks have TWO catalytic converters, one driver side, one passenger side. Refered to respectively as Bank 1 (Driver side) and Bank 2 (passenger side). This also helps with knowing firing orders. Cylinder 1 is on Bank 1. You can figure it out from there. There are no resonators, besides the muffler.

Most older trucks will have two, but they are normally in-line and not side-by-side.

[ukrkoz]

yeah, they do. it was late night and pouring down to go outside and pick under the hood on mine. Chilton has always mentioned only singular, converter, not plural. so i stated.

i think, my guess was right then. should be the Y-shaped connecting pipe between cats and central exhaust downline, unless he has it modified or something. i'd definitely look at that brown "donut" inside the flange first. if it sound like machine gun, it's exhaust blowing out somewhere.

[iroc343]

Sounds as if you think you've found your rattle. My 2005 2500hd does the same thing. I wonder if it might be the torque converter? Sound seems to come from that area. No other signs, transmission works fine, done it for quite awhile. Just thought I'd throw that out for consideration.