my buddy is working on a 2006 Dodge 2500. He went to adjust his valves the other day and was wondering if a harmonic balancer can be installed wrong. When trying to find TDC and having the mark at the 12 o'clock position, the #1 exhaust rocker was loose but the intake was not, he proceeded to rotate the engine 360 per instructions and still both were not loose like the instructions state. He did this two more times just to double check with the same results. When the TDC mark was at the 6 o'clock position then both intake and exhaust were loose as well as the others that needed to be adjusted at TDC. When he rotated the engine 360 degrees from this position then #6 intake and exhaust were loose as well as the other corresponding ones that needed to be adjusted at that position. Could the harmonic balancer have been off when the previous owner did a crankshaft seal and installed it differently? Seemed, if this can be done, it would make it easier to find TDC from under the truck using the harmonic balancer bolts to rotate the motor by yourself. Thanks for any help.