I am having to replace the oil pump on my '05 (4.7) and clean up some sludge. I have the valve covers off, and notice the cam on the passenger side is correct, but the driver side one is advanced about a tooth. Chains are tight, can't wiggle the cams at all. Was this common, or do I have another issue? Didn't want to have to replace the chains if I don't have to, but will if it's a concern