OK...here it is. I can floor it, run it as hard as I want on flat ground and no knock. 30 seconds into a hill and it starts clacking. only a 4% grade or higher. 30 degree cold night, 90 degree day...same same. When I crest the grade and head downhill (I do this drive every fri and sat, you go from a 6% up hill to a 6%+ downhill in 30 seconds) it's still there if I give it 1/2 trottle or more. Then, after a 1/4 mile or so down the hill, it goes away, but it's gradual. 92 mazda navajo, 5speed, 4L ohv. Full oil(15W40).
Almost seems like it's starving for oil, like the clack when it hasen't ran for a couple days, that first second after it starts, but oil psi is good on the gauge. Any thoughts.