My truck I used to tow with has a squeaky noise from underneath, sounds like it's from the rear. Checked rotors and calipers as well as parking brake, u-joints, leaves... sprayed some lubricant underneath everywhere still squeaking but only in reverse but a little quieter now... It's only when you back up??? In gear or coasting...2004 Dodge Ram 2500 Hemi 4x4, any ideas? It has 40000 km and only averages 7000 km a year.