plow

i have a low rpm noise that i can't locate. it sounds like an air leak and you can only hear it when truck is in gear, you can hear it really good at about 1800 rpm. ihave taken it to the dealer ship but they can't even hear it. when you get rpms up and you start to hear the noise if you press the clutch the noise stops? any help would be greatly appreciated

infidel

Throw out bearing?

plow

thank you infidel for your response i was thinkingthe same thing i have ckeck just about everything i know of i even thought about going ahead and changing intercooler boots but engine hasplenty of power and those boots are exspensive but your the only one that has even guessed at what it could be. i was also thinking about vp?

infidel

Take a good look at the pass side lower boot, it can get cut by the edge of the fender. It doesn't look like it but will touch when you have boost since the boot puffs up. I've seen a couple where you couldn't see the cut with the engine off or idling but could stick your finger right though the cut.
Still doesn't explain why pushing in the clutch whould make the sound change though.
Don't understand what you mean by vp, if it's injection pump your 12 valve doesn't have a vp.

plow

sorry infidel what i call vp is a vaccum pump. could what i am hearing be coming from passenger side i am hearing it more on drivers side, it seems to be consistant with a vibration in the steering wheel and shifter ,accelerator it will put my foot asleep on a long trip. would the leak in the passenger side intercooler boot affect engine power because as far as i can tell it still has plenty of power, but i will absolutly take alook at the boots again i never took them off or anything i just sprayed soapy water on them at idle. when i press the clutch boost stops that might explain why the noise stops when i press clutch?

infidel

Yours is a tough one to diagnose without seeing it in person.
Does it do it even if the truck isn't moving?
Might want to check for loose motor or tranny mounts.

plow

no it dosen't do it when truck isn't moving. even the people that has seen it can't figure it out. but i'll check those motor and tranny mount's first thing tommorrow thanks for your help