Damper/Balancer = same thing. Yes it can be removed with engine in truck, but you'll probably have to pull the radiator at least, you may consider pulling the grille for easier access as well. I pulled all this stuff apart on Thursday in preparation for new cam and lifters, so it's still fairly fresh in my mind. Was easy for me as all the front sheet metal and radiator were removed from my truck already. The Balancer is "keyed", so it only comes off and goes back on in the same place. It is pressed back on over the key. I havent gotten this far, as my new cam isnt here til late this week, and I'll be installing a double pulley balancer in it's place to run A/C and a PS pump. But I assume it just needs to be tapped back onto the crankshaft as far as the pulley lines up with the one on the water pump above it. One other note, you may want to check carefully, or as mentioned above, replace the timing cover gasket when youre in there as well. Mine was literally "petrified" when I pulled the cover.
