Just wondering if any of you have ever had this happen when servicing your trans... dumped the fluid and changed the filter today, filled with 4 qts of dex 6 and Upon start up the trans made a very loud metallic grinding sound.

I shut it down after about a second of running, then restarted and it made the sound again. On the third start up it made no noise at all...

Ive done fluid and filter changes on plenty of 4l60's including the one in this truck and have never had this happen before. What gives?