Re: Transmission Fluid
Ford puts Mercon ATF in Manual Transmissions and that is what is recommended. Other vehicles use ATF in manual Trannys too. Use what the manufacturer recommends. Look it up in your book and dont do otherwise. If you want to flush it, then do so with Mercon, Drain, refill drive 10-15 miles, then drain and refill it again. Then run a hundred or so and do it again. That should do it. Watch for leaks closely. Someone may have put heavy oil in to slow down a leak. Generally, the thinner the oil the better lubricity, if it is the right application.