2001 Dodge Ram Truck shut down while driving.

The other day I was driving along everything was working fine and my check gauges light came on. My oil pressure gauge said I had no pressure but then the needle would jump back up and say that I did, and my check light went off. Well i've had this problem before so I just disregarded it. Well about 5 miles down the road from there without any warning or any kind of sounds my truck just completlely shutdown. I pulled it to the side of the road and had it towed home. I replaced the battery, crank sensor, crankshaft position sensor, coil, spark plugs, spark plug wires. Still nothing, I had a mechanic look at it and he said I had spark and fuel pressure. He then said that my timing chain had broken, but he didn't pull the cover off. Well i'm not convinced. Please help. Thanks.