Gear Lube for 4.10s????

hi im new to this board..i have a 2003 GT, and i just bought the motive 4.10s from mustangtuning.com. I told the installer that ill buy my own oil and he said you need 10 litres of it. Do i really need that much oil or did i hear him wrong? is amsoil synthetic 75W-140 the best mixture to get for my gears and is friction moditive necessary and is one of those little bottles enough?? Please guys i need your output on this..thanks

daver01 said:

i just bought 2 bottles (qts?) of the mobil 1 synthetic & 1 tube of friction modifier. should be all u need. i'm not much on the metric system, but 10 litres sounds like alot. 2 bottles will be enough.

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ok i dont wana confuse you guys since most of you are from the U.S....and im buying it from amsoil anyways which is in quarts anyways...so would 2 quarts be enough?? all that hes doing is replacing the stock gears with new 4.10s..should i buy only 2 or 3 just in case?

i asked this question on modulardepot aswell and from both replies combined i came to the conclusion that 3 quarts should be enough so ill buy that much just incase and 1 tube of friction modifier aswell. About which blend to use? it was the guy who told me to get synthetic 175w-40 and also recommended amsoil to me. And about his "pro"fessionalism. Hes like 34 years old...hes been a mechanic since he was a kid and now he only specializes in transmissions and differentials doesnt do anything else so he knows gears like the back of his hand. And if your wondering maybe he doesnt know about mustangs well he had a 2001 GT convertable before and he installed 4.10s on it himself and now he sold it and bought a 2003 cobra convertable and installed 3.73 gears on it aswell ...so i doubt anyone found a more professional guy than that lol ...and hes my best friends uncle so if anything goes wrong he ll gladly fix it free of charge...and thanks for all the guys who replied