The clacking/tapping noise from the engine I've been told might be a loose wrist pin has got me wondering. The tapping (which changes speed according to RPM) noise seems dampened when I turn sharply, and in 4wd sometimes the truck seems to shudder when I try to turn and I'm going slow (not sure if that's related, or just a side effect of 4wd). Could the tapping be the power steering pump? It doesn't feel like I've lost any power steering control, but maybe I'm just used to the lowered performance? I've also had a bad water pump that had to be replaced about 3 years ago, could it be that? Do either of those make a clack/tap when they're going out?