yep, the infamous worn out rear seal. Not a biggie to change, expense-wise. Takes time to do in the driveway, about a full day if you've never done one. Gotta drop the trans, remove the flexplate, pull the seal, install the new seal and put it all back together. The seal comes from GM with a white plastic ring in the ID of it, leave it in there and just shove it into the seal bore. The plastic ring keeps the seal expanded so that is slides onto the crankshaft.