While manual and automatic transmission fluids do the same basic thing, mixing them together is not a good idea. In fact, ...

Read more: 10 Best Motor Oil Brands, Ranked It's super important to choose the ... the owner's manual will probably indicate ...

While the 6R140 transmission in your Super Duty behaves like any ... Replace the transmission fluid and filter, using the correct ATF along with a filter with the good O-ring.