I believe ALL Dexron fluid is backwards compatible, so any Dexron you care to use will be fine. The capacity of a THM350 is about 20 pints, so I would expect the ST300 to be similar. Are you starting with a completely dry transmission and converter? If not, you will only be able to get 8-10 pints out by dropping the pan.
I'm getting ready to head over to the local Walmart and pick up some transmission fluid. I'm reading that the synthetic transmission fluid is better on the st300, is this true? Or does it not matter? Which type should I buy? I'm also planning on using the Lucas Transmission Fix before I add then new fluid. Any tips would be great. Plus, have to flush my radiator... I didn't flush the system before I replaced the old radiator.. I bought a bottle of Bar's Leaks radiator flush has anyone had any success with it?
