a new noise ??

[BIG JOE]

Ok , I read the "this" thread that bjs suggested . My problem is not when I'm sittin at idle & my truck dosnt shudder. My problem is constant & when I start to hear the noise it starts quoet & gets loud quickly . While in neutral it happens when I bring the rpm up to between 1000-2000 rpm & the same while driving . If I accelerate the noise will go away untill I level out then it comes back . The noise is difficult to explain, its almost like a rubbing sound mixed with a helicopter ??? If that makes sence . I do not feel it in the truck . While in neutral if I bring the rpm up to say 1500 rpm , when the noise starts up it drops the rpm down to about 1100 rpm ? Thanx so much for any help

Don't know fer sure but I wanta say.... Check everything Serp belt driven.. the PS pump, the tension-er, alternator, fan clutch, water pump... look for wobbles and flapping of the belt as it passes each one.

I say this cuz as you desribe it.. it seems it's a RPM driven noise associated with a load that changes the RPM.. in gear, outa gear, moving or at idle.....

A SWAG but worth checking first ?

Joe

 

[BJS]

yes clutch engaged being foot off the pedal and power from the engine turning the input shaft of the transmission.

 

[fordfury]

sounds to me like a warm up valve on the turbo what is the outside temp.