What Kind Of Tranny Fluid For A T-5???

[PKRWUD]

Not flaming, just sharing. The factory fills T5's with Dexron II. In '88 and later Mustangs, T5's came filled with Mercon ATF, Fords nearly identical twin to DexronII. Although Mercon ATF is the OE recommended lubricant, it is known to become marginal in severe service. The World Class T5's use of organic linings on it's synchro blocker rings' inner core surfaces makes the use of OE-grade DexronII or Mercon ATF-compatible lubricants mandatory. F Type ATF should never be used in a T5, because mating-surface and/or friction-surface damage will occur. The same is true of gear oil. Because standard gear oil is too viscous to flow through all of a T5's needle bearings and lube passages, extensive transmission damage can and will result from it's use.

Take care,
-Chris