Update for anyone interested. It's at another shop, actually the best shop in the area...usually only does custom stuff on vintage cars and rear and motor work but I know him and he's kind of doing me a favor looking it over. Transmission is out and the rear main is dry, top rear of the oil pan gets wet but nothing making it to the ground. It's very strange, you can run it for an hour and get no leak, then at other times it will leave drops on the ground. Going to order a new GM oil pan and hardware and see if that stops it. No way of knowing if the other shop tweaked it or not, don't know if they over torqued or tightened out of sequence. If this doesn't work I will be traveling with a piece of plywood to put under it, as there is nowhere else to look.

 

i also have a sizeable leak on my 2001 6.0. did you ever resolve this? mine also seems to vary...some times just a drop or two....sometimes its more like a 3 inch puddle!

 

I spent $4000 trying to fix it and I now have a piece of plywood under it now to protect my driveway. 2 shops, and countless hours, parts, and money and it can't be stopped. The last thing tried on mine was a new factory oil pan, gaskets, and bolts. This was installed with the transmission out so they could check the rear main. I hope you have a better outcome, and I'm sure you will, it's just that my experience can't help you. There are some things that just can't be fixed within reason, such as my truck. Good luck with yours.

 

I did not read all the post , but if someone would use dye they should be able to locate the source of the leak.

 

There was so much dye in it that the oil on the ground was orange. The last shop spent 20 hours on it, had it running with the tranny out for hours. They even kind of criticized the first shop for giving up, saying they would never do that. Mind you this is a very highly respected place that only does specialty stuff, and I know the owner a long time. They said the same thing as the first, has to be the oil pan. They went through the procedure for installing the brand new one meticulously....this leak can't be found without getting NASA involved. It is an inconsistent leak, takes days to show up after cleaning things up, but always comes back. At this point it is far past wasting money. I have run out of options within normal channels. I never thought I would say it's unfix-able, but not another penny from me. It will be traded in as soon as possible. I hope no one else has a similar experience.