http://www.youtube.com/watch?v=414gmYcGb-g

I took the serp belt off to eliminate accessories as a possible cause.

Give me your best guess.
I think its terminal. Unfortunately...

 

outside of the raspy throtle, what seems to be a vacumme leak, and that nice knock when you idel down.

Seems like maybe the Torque convert has let loose. (which could be the knock when you let off the throtle).

Maybe some of the better hearing folks with mechanical backround can respond better.

 

I wasn't able to listen to it at full volume at work, however, it is quite possibly a broken flex plate...

 

The other noises are actually aheathy cam with the exhaust run through a glasspack, and bouncing off my garage walls. I think the vacuum leak your referring to is my intake sucking in air. Its that rattling noise that has me concerned. I found a used 4.3L V6 from a fullsize truck with 92,000 on the ticker for $350. Everybody else wants $400, some with a core, some without. This guy pulled it for someone else, who ended up nothaving the money.

I am looking at two possibilies, one in the oil pan and the other the flexplate. To get the flex plate out it would be easier to remove the tranny. To get the oil pan off, I have to remove the front axle and hoist the engine up a couple inches. About the only common ground between the two is removing the front driveshaft and torque converter cover plate. Now if I have to pull the engine, removing the front axle wont help me much. Someone in another forum suggested a loose rod/main cap bolt. Decisions, decisions???

I guess tommorrow I clean up my garage floor and put the front end on jack stands. Pull the front driveshaft, starter, and torque converter cover. On one hand I hope its the flexplate (faster), one the other hand I hope its a loose nut (cheaper). I have till a week from Monday to have what ever is broke fixed. Gives me some time, however I am going 4wheeling this Saturday. I'll keep you all posted on my progress.

Still looking for ideas.

 

I'm also thinking along the lines of a loose or cracked flex plate.
When you did your tranny, did you locktite the bolts?

 

Wow, not bad for a Deaf person to hit so close to every one else.

And they say we are not good at mechanics [sm=happy046.gif] [sm=icon_cheers.gif]to ya!

Bet this post will take most by surprise.
Again I would lay my odds more on the torque converter due to the more of a single knock over a raspy knock. A raspy or multi point knock would lead to other issues like Rods or mains. And it feels way Differently then what you have recorded. It feels more like the clutch layers in the torque converter kicking back one clunk over slapping around like a piston rod.

 

It gets way louder when you're under the truck, so either it's something in your bottom end, or on the transmission side...

Try having the camera directly under the trans when you give it a couple revs... If you haven't taken the truck apart yet, lol

 

Update.
I finally got some time today to spend on it. Tranny bolts were loose. Tightened them up, howver it still rattles some. Dropped the torque converter cover plate, which means pulling the front driveshaft, and starter. The flexplate doesn't looked cracked, bent propable. I have some nice little grooves on the edge of the flexplate gears teeth and on the starter gears. Been some grinding going on.

I also had a leaky water pump. Replaced that already.

Regular flexplate is $22, heavy duty version is $53. Thinking of going with the heavy duty version, and def need to put locktite on the tranny to engine bolts. Something so simple can really bit you in the butt.

I wont make that mistake again.

 

Its a common rule for anyone doing bolts that take more then 12 ft lbs to use locktight (unless its a Harley then use it on all of them).

Sometimes the simple things will vibrate loose and make it seemlike something more serious.

Glad it was not anything too major. Like driving down the road and it comes apart.

 

I reccomend the blue locktight, not the red, unless you plan on never taking those bolts out again...