Hello all,
Im not sure how to describe the sound im hearing. Occasionally when I roll up to a red light and the truck is sitting there idling, I get a weird "howowowowowowow" sound for a few seconds then it goes away. Before I realised it was my truck I thought it sounded like a fire truck horn in the distance... I know this is a terrible description of the sound but I tried to record it and of course it stopped doing it. Gonna try again later, but if anyone knows what Im ttalking about Id appreciate your suggestions as to what might cause it!
Thanks and sorry again for the vague description.

 

I should add its a 96 f150, efi, m5odr2 trans and the sound seems to happen when im in neutral or clutch in at a stop.

 

Check your pulley and accessory drive bearings on the belt-driven stuff at the front of the motor first. Failing bearings can howl.