2000 Dodge Intrepid knocking

I am experincing a loud knocking noise from my engine. So I took it to a shop and a guy looked at it and told me it needed a new engine. So I got more input by a few more people and 2 out of the 3 said its the bearings on the bottom of the engine. I think they said a rod bearing is bad. So what I want to know is do I have to pull the engine to replace them cause I was told I have to do that and the engine comes out from the bottom. I figured all I have to do is pull the oil pan off and take them out that way. So whos right and whos wrong? And could it also be that it could have jumped timing? There is no drop in oil pressure and the oil looks good, no leaks, or smoke from the engine infact last time I drove it home from the shop it still ran strong.