Well, I finally got around to dropping the tranny. First thing I noticed was how hard it was to turn the crank(Flexplate was rubbing on the bellhousing/block/oilpan). Then I found that one of the torque converter bolts were missing and another I was able to remove by hand.

You can see in the pictures where the flexplate was rubbing on the bell and it also ended up taking a chunk out of the oil pan. Hopefully everything else is fine

 

On my 2500HD I pulled the motor and found that I had cracked the flexplate in a circle around the bolts to the crank. These stock flexplates dont seem to be able to handle high torque quick take offs lol. I went an got a tci heavy duty flexplate pretty reasonalble priced. They are reinforced around the mounts and alot thicker. If you break one you got a problem. Youre lucky it didnt cause even more damage.

 

ouch...

 

Man, you have a laundry list of **** gone bad there huh!? Starter, flex plate, bolts, cracked oil pan, leaky rear main seal...geeez...I'd give Chris at Circle-D a call and get both a converter and high perf flex plate...you won't have to get new converter bolts as he puts good hardened ones in the box with the verter.

 

I already picked up a flexplate and converter. I was kinda hopping the block was bad so I could drop in an ls1. I saw the minor leaking but never noticed it on under the truck or on the driveway

 

Bolts backed out and caused most of your issues IMO. Your actually lucky it didn't cause more damage, or unlucky since you want an excuse to drop in an LS1!