I have an 86 F-150 2wd, with 300 6 cyl., and 4 speed manual transmission. The 4th gear is actually an overdrive gear. Seems to be a lot of confusion on what fluid the transmission takes. I figured regular 75-80W gear oil but Jiffy Lube says no, take special fluid. Called Ford dealer, no answers. The book calls for Ford spec ESP-M2C83-C OR WSD-M2C200-C. (The Ford parts guy says the numbers are confusing and he did not not know WHAT to recommend. Seems like it would not be such as tough thing to find out. I see where one guy used Mobil 1 75-90W in his, even though they (Mobil) told me they had nothing equal to Ford spec. ANy of you that have an 86, what do YOU use??