I happen to stop by the local Ford parts store and asked them for a couple qts of 75W-90 weight non-synthetic gear oil and he said all Fords use Full=synthetic gear oil (XU-75W140-QL). He wondered why we were using the Non-synthetic gear oil. Could some one explain the difference to me?

Thanks for you help,

Duzie/Guthrie OK MK4 F5R1007406RD