Changing fluids, need some guidance

With the rearend i think its something like 2 bottles of fluid(not sure how much is in the bottles) and the friction modifier comes in a little bottle and you put all of it in there. I used Royal Purple rearend fluid

T45 and TR3650's take almost 4 quarts of ATF. Have the car on level ground. Fill it through the shifter with the fill plug out. Put a catch can under the car and when you see fluid dripping out of the fill plug, wait until it stops dripping and put the fill plug back in. This ASSURES you perfect fill up.

8.8 rear ends take almost 3 quarts of gear end fluid and 4oz. friction modifier. Put the friction modifier in first. You'll have to jack the car up to get under it. Treat the rear end the same as the transmission. Once you see fluid dripping out, set the car on level ground, let the fluid stop dripping out, then put the fill plug back in.

You do NOT want to overfill either unit because this could cause the seals to blow out. The rear end vent will usually let out access fluid, but only if it's a tad overfilled. If it has too much in there, it will drip out of the wheel seals and the inside of your wheels get coated with fluid.