Need some help with my 727 Auto Tranny.....

I usually do this myself, but I took my '70 Duster by a transmission shop today, to have them check my stripped bolt hole in the tranny pan. Well upon draining the fluid, and taking the pan off they found metal shavings(at first the guy said iron, then steel, and then finally deciding on calling them metal) on the bottom of the pan, as well as in the fluid.

The tranny was just rebuilt 1000 miles ago by Shift Management in Sacramento, CA. So I don't see how it could be going bad already?

But the thing that really irritated me, was that they F***ing put the old trans fluid back in.......(the fluid with the shavings) I'm going to redrain it tomorrow before I drive it for any length of time.

I have had no problems with the tranny shifting either. This is on a 727 auto trans.

So if you guys have any ideas on what the shavings could be I'd appriciate your in-put!