Loud Explosion Or Noise 2500 Hd

[JoJoJim]

I have a Chev 2500 HD Crew Car 4 WD 8.1 Allison with 151,000 on it. Several times over the last couple of weeks within a few seconds after start up I sometimes I get a loud report possibly like a backfire. I can feel it on my feet and more so on the passenger side. I checked ball joints and tie rod ends to try and make sure it wasn't one of them and I don't think so. I cannot see any sign of a blown head gasket. I think I have started to move the steering wheel when it happens but do not feel anything from it. Any ideas? I have dual flowmasters on it and there is a small hole in one but those are clear at the back.

[Kodiak450]

I have a Chev 2500 HD Crew Car 4 WD 8.1 Allison with 151,000 on it. Several times over the last couple of weeks within a few seconds after start up I sometimes I get a loud report possibly like a backfire. I can feel it on my feet and more so on the passenger side. I checked ball joints and tie rod ends to try and make sure it wasn't one of them and I don't think so. I cannot see any sign of a blown head gasket. I think I have started to move the steering wheel when it happens but do not feel anything from it. Any ideas? I have dual flowmasters on it and there is a small hole in one but those are clear at the back.

 

Well to rule out mufflers, get yourself some muffler tape (which is inexpensive) and seal up the hole. Then see if you still hear noise. How old are the plugs? Are they all tight? Loose plug could cause a noise like that and as engine warms up it could go away some.