I have a 98 Nissan Frontier. Truck was running fine one day and the next day it started ticking. Shut it down and now it won’t start. People are telling me it my timing chain. Is that true? Took the valve cover off and the both chains are still good. I can turn the crank clockwise and both chains turn but when I turn the crank counter clockwise neither chain will turn (is that normally)? I have taken pretty much the front of the motor off and the only things left is the AC compressor. Does that need to come off? Also what else needs to come off before I can start unbolting the timing cover? Any help would be grateful.