I've put 130,000 on a 96 Ciera in three years and got it with same. Changed the oil, bent the air conditioner pully away from the belt, (lost the fluid strangely after flushing the radiator at a national oil-change stop) replaced a tensioner. The transmission fluid was changed right away twice to clean it out, and then not changed. It never leaked but shifted up rough once after coasting down-hill into town a few weeks ago. Then going uphill a week later it would not shift up. Got about 25 miles in 2nd going slow, and then it simply slipped completely. Parked it right in front of a church. I could start it up and go another mile before same thing happened. Got to the garage the next day five miles away doing this. Is this a sensor problem (when warm - clogged or shot) or is this a tranny gone with 260,000? The tranny fluid went from rose to black in a hurry.