Type F has its uses though. I reccomend it for your power steering pump. Doesnt break down, as streets said, and it is cheap. However, for trannys, go with the decron III, and dont use any additives unless you have severe slippage. These seem to have little to no beneficiary effects on GM transmissions, and are a general headache to clean out of the pans for a filter change. Also, i have to ask, whats the difference between decron III and decron II?