Quote Originally Posted by Mike P View Post
I tend to agree with the others the other that your initial problem was likely not having enough fluid in the transmission initially. My experience is you normally lose a minimum of 4 quarts of fluid just dropping the pan on a TH350. A dry convertor will normally require anywhere between 2-5 more quarts and a drained cooler and lines could hold up to an additional 1 quart.

Now some more bad news for you. You probably smoked the clutches and/or bands and some of that material likely migrated into the convertor and is sitting in the transmission cooler and cooler lines. The cooler and lines are not a big deal....they can be blown out. Besides getting a bunch of crap in the convertor, running the car extremely low on fluid possibly also damaged the internals of the convertor. Yeah, I'm saying to be on the safe side you will also need to replace the convertor again........or you can take a chance and possibly have to do everything over for a THIRD TIME. That is why new/rebuilt transmissions require a new or rebuilt convertor in order for the warranty to be honored.......and believe me what you now have now is a used convertor.

Here is the procedure I normally use to initially fill a new transmission/ torque convertor.

Before installing the convertor into the transmission slowly put a minimum of 1-2 quarts of fluid in it. Once the transmission if installed and everything hooked up add 4 quarts of fluid to the transmission. Start the engine (on slow idle) and immediately start adding fluid checking the level often......helpful hint if there is no fluid showing on the bottom of the dipstick a full quart at a time can be added. Check the dipstick after each quart. Once the fluid level reaches dip stick add fluid a 1/2 quart (pint) at a time. Once the fluid is between the add and full line, get in the car put your foot on the brake and run the transmission thru the gears, put it back in park and recheck the level. I usually stop adding fluid when the dipstick shows it is about 1/2 a pint low (between the full and add marks). To properly check the fluid level the transmission needs to be a full operating temperature and that is not going to happen idling in the garage. Check for leaks then take the car out and drive it easily for a couple of miles, go back to the shop and recheck the fluid level.....add fluid if necessary.

Here is a link to a fluid capacity chart.

https://www.tciauto.com/tc/fluid-capacity/

THIS IS JUST A GUIDE!!! Due to differences between stock and aftermarket transmission pans, coolers and cooler lines and convertors the only real way to check the fluid level is with the dipstick.
Excellent advice, Mike! Especially the shout out at the end about it the capacity chart being a GUIDE. Some OEM coolers internal to the radiator hold a lot more than a quart if additional fluid, from what I remember.