I buy by the gallon, so I bought 3 gallons when I did mine.

If you buy by the quart I'd buy 10 minimum, just to make sure you have enough.

I did a pan drop and changed the filter and I think I used 9 quarts. Mouse'* estimate of 10 should be good.

Thanks for all the help. I did a pan drop trans oil/filter change yesterday and 9 gallons did the trick. My filter was bearily hanging on. The collar was extremely worn to where the filter was being held kind of in place only by the pan. The wear marks on the inside were proof of that. No chunks though so im happy.

Did you cleanup and reuse the gasket, or did you use the crap that comes in the box?

"9 gallons did the trick"

I think you mean 9 quarts?

He might have changed the fluid in the valve body and torque converter too.

you are correct, 9 QUARTS. i reused the factory gasket after cleaning it up.

I think the "official" GM Forum measurement is about 7 to 7.5 quarts, for just a pan drop and filter change. If you drained out 9 quarts, then congratulations, you somehow got more dirty fluid out of your car.

Filling a bone-dry transmission after a rebuild, replacement, or torque converter swap will take up to 13 quarts. That'* about all our transmissions can hold.

Then I'm gonna call the "official" measurement crap. Every time I've done a pan service on this transmission, or heard of anyone else doing one, it'* been 9 quarts. Of course, most people that are DIY let the transmission drain for longer than the 20 minutes it takes to do the job.

Took 9 quarts to fill to the top line, not sure what else to say...... maybe I was low to begin with or as Mouse said the "official" isnt accurate. I was working with Billboost and he was expecting to put 9 in before we started so it seems to be the average number for a pan drop.