lots of noise from upper end- help.

[97whitewhale]

97 f350 auto 7.3 with 389,xxx on it. starts fine, very little smoke/blowby .at idle it sounds like the motor is going to blow into peices, give it a little throttle it goes away. drives fine with normal power until it has to idle then the sounds come out. so far i have ran it without the belt to eliminate all acc. noise, changed oils and checked every bolt in torque conv. done the probe to ear test and it is louder on the front of motor.
im lost from here, new to me this diesel stuff. anyone got any suggestions short of a new motor, and anyone in the st.louis/ st.charles mo. area care to listen themselves? thanks

[AD5GB]

Not sure what you mean by that, but 7.3s are VERY noisy. I hate getting under the hood of mine when it's running. In fact when I have to, I usually wear ear plugs!

Can you describe what you're hearing or post a clip on youtube or something?

[97whitewhale]

it sounds as if all the rods are knockin in same time, then it will "clear up" for a second run smooth then go back to knockin. but if i throttle it up just a little bit it all goes away and runs just fine with the normal clatter.

[97whitewhale]

also can compare it to a truck without being plugged in at 0* and starting up. lots of noise!!!

[97whitewhale]

well ive narrowed it down to .............cracked flexplate.

[AD5GB]

Dang! I'd have never guessed that without hearing it.

[97whitewhale]

still cant believe it myself. but i can see the cracks coming out from the center and the bright metal where its been rubbing. now im waitin to see how much shop wants to fix or if im gonna do it myself.

[AD5GB]

It's not a bad job with a trans jack. Alldata sets the job at 4.8 hours labor. If you take it somewhere, don't let 'em charge much more than that.