Wierd Sound from LLY

[WPatrus]

My LLy in my sig has been making a strange sound when at idle (normally at stoplights or when reaching destination.

It sounds like an old alarm clock, with the ringing sound. It is not over powering but it can be heard clearly at idle over the engine and exhaust. The sound seems to be coming from the passanger side of the engine towards the back around the transmission. I can't seem to pinpoint it more that that though. It's a bad rattle thats more annoying than anything. Everything runs fine and it has not performance issues. I also can't hear the sound when I am on the throttle but that doesn't mean its just not being overpowered by the engine then.

Long Post, sorry - I tried this question over on the old site but I never got a response - anybody have any ideas here? Just a shot in the dark I know.

THanks anyway.

 

[BudTX]

Are you sure that it is not more of a pump type noise? The pump on your Allison can be audible.

 

[mattydmax]

There is also an exhaust shroud between the downpipe and body if I remember. Haven't been underneath for a while. My wife's Suburban had a loose shield and it sounded alomost like a ringing/rattling noise. Sometimes something loose like that can give off some strange sounds. Kind of tough to diagnose the noises over the internet.

 

[tomrex]

X2 on the exhaust. Stick your foot on the tailpipe and see if it goes away.

 

[tomrex]

When all else fails, kick the m'fer.

 

[WPatrus]

I have duel MBRP's so it's hard to cover it up to see if it rattles that way. But I will climb up under it and try to find that heat shroud. That sounds kinda like it might be the culperate but I'll let you know.

THanks guys

 

[Golddigger]

When I put my aftermarket exhaust on I had a ringing at idle. It was those annoying washers that go on the hangers dancing around.

 

[jcool]

put on some gloves and tighten everything down while its hot.

 

[WPatrus]

I just got finished working on it now. I took off the wheel well liner and tightened the shroud and heat shield near the down pipe. I tapped it with a rubber mallet and found that is where the sound was coming from. I guess the test will be the ride. I'll let ya know if it comes back.

Jcool I see your from Jacksonville - I'll have to look you up next time I am up that way. I am from Wilmington / Wallace originally and have family strung all around the area (it's still home ya know).

 

[WPatrus]

Little update on the rattling. It's gone! MattyDmax was right - It was the loose shield. In particular it was rattling on the downpipe.

Thanks again guys

 

[BudTX]

I am glad that you got it figured out.