knocking/slapping noise while deccelerating
I have a 01 f250, 7.3 L, with a zf 6 speed trans. yester day while i was coasting down hill in 5th gear i heard a faint knocking noise sounding like it was comming from the tranny. at first it would only do it going down hill, but now has gotten progressively worse. the noise is very loud and it jolts the truck, and it does it almost every time i take my foot off the accelerator (flat and downhill). it happens in 5th, 4th, and 3rd (i imagine in all the lower gears as well but haven't tried to make it happen in those gears).
I checked for play in the drivline, its good, u joints are not hot at all. tranny and tcase and rear end are warm but not hot. the clutch seems to be working fine, and there is no problems accelerating only decelerating (when i take my foot off the throttle).
Please help! I need to tow with my truck next week.