Still Trying To Trace The Knock

[Drg racr]

I took some rubber hose and crawled under the Ex today. I can hear it loudest where the starter goes into the bellhousing. I let it warm up about 10 min then I can really hear it. No shavings in the oil, and I've put almost 5000 miles on this knocking.
Cracked flexplate?
Can I pull the oil pan without pulling the motor out if I have to?
I was thinking it's a wristpin, but when I removed the spark it didn't change it. Usually, if you take the load off the cylinder, it will calm down.
This truck has always spark-knocked.

 

[mr.steve]

automatic or stick? torque converter tight? knocking change tones or intensity with speed/load? if it's automatic checked the fluid level and smell? those torque converters will sound just like a rod or piston pin.

 

[Drg racr]

It's an automatic. The knock is the same tone no mater what I do. THe fluid level is good, I just changed the fluid and screen a few months ago. before the change it did smell old, but not burnt. On a side note, the lockup quit working at about the same time this started.