My wife ran the van low on oil, as she was going to get an oil changed , she noticed the oil light flickering. With the new oil in now there is a loud ticking noise coming from the engine. It isn't as loud at an idle but when you rev it up it gets louder and faster. Could this be a spun rod bearing? also can you replace a 3.8L with a 3.3L will it bolt to the transaxle and cradle?