eb/ed manual states that v8 uses gear oil...I don't have ef/el manual .



both w/c and non w/c used dexron in the 6 cyl..
im not sure why the v8 was listed as using gear oil when its kind of the same box except for the obvious..

either way you can use synthetic gear oil in t5s that originally had dexron trans fluid..

The EBII owners handbook I have here specifies 75/90 gear oil for the V8 T5

I have used Penrite Gear Oil in every T5 I have had, I've had one for over 100,000k's (its got 300k on it) and its still going strong.

The reason they started using Auto fluid is the EP additives in gearbox oil. Where extreme pressure (EP) is applied, ie where the tips of the gears touch, the EP additives in the oil essentially drop metal out of solution onto the teeth to protect them against wear. However this f**k with the brass synchros in the T5's. The answer is Penrite's Gear Oil that doesn't have EP additives in it. I looked into this quite a bit when I started upgrading my engine, as I didn't really trust something as thin as ATF to protect it. The gear oil does a great job, gear shift is still smooth (well, for a T5) and doesn't feel notchy on cold mornings. But I feel like its petter protected with a fluid that is designed for use on gears, as opposed to in torque converters. The requirements for an ATF are different than a gear oil.

ATF does lubricate gears in an auto, as well as axial slip ring type seals, bearings and bushings.