infinityisfive

Hey guys last weekend the truck started making a funny noise. I have an 89 pickup with the 3vze and auto transmission and about 150k miles. We were driving up the mountain and suddenly heard this beefy, rotational rattle coming from the engine. I checked the oil and it was fine. We thought 'water pump' but there was no water on the ground. We had it towed the way home :-(

I was thinking timing belt or the guides but the noise is loudest behind and below the engine. I searched the forums here and we think it's the tranny flex plate. We do a lot of driving on dirt roads and I believe one of the bolts holding the plate on might have come loose and be what's causing the racket. When heard at higher rpm (3k) it gets louder and you can hear the engine over the racket - and the engine itself sounds normal. I'm not a mechanic and any help would be appreciated. If not the flex plate then something else to do with the transmission? I'm about to get under it and check things. Thought you guys would know what to do. Here are a couple videos (with poor audio) of whats going on

http://www.youtube.com/watch?v=_rSSY7WsloE
http://www.youtube.com/watch?v=-xf0fGeGuTg

what do you guys think?