You've already got 4 in the tranny and 2 in the TC. Now, pour one more quart in the tranny. Start the truck up and let it run for 20 seconds. Shut it off. Check the dipstick, if it is low, put another quart in and let it run. Check the dipstick to make sure all of it doesn't get sucked up into the tranny and the cooler. If the level looks ok, get inside while it is running and cycle it through the gears while your foot is on the brake. Don't go anywhere just put it in reverse for a few seconds, then neutral, the OD and so on until you go through them all. Check your fluid level again, add more if you need to until it is at the right level and at operating temperature. Take 4 quarts of tranny fluid with you and something to wipe the dipstick off with. Start driving. Take it easy. No jack rabbit starts. Go about 1/2 a block and get out and check the level and add if necessary. Now go all the way around the block and check again. Now that it is up to level and you are sure there no external leaks(tranny line connections, etc.)get in and take it somewhere where you can get into OD for a little bit maybe a 1/4 mile. Pull over and add fluid. As the input drum and reverse input drum and case passages fills, it will suck up more and more fluid. Make sure you don't overfill it as it may cause it to overheat. Don't let it go dry, you'll overheat it. Now all of this is provided you overhauled the tranny. If not you do the same except you just won't need as much fluid.
HTH,
George Blake
