There are as many recipes for this question as there are pizza shops in columbus. Keep in mind that mercon fluiid is already partially synthetic. This was done to limit varnish buildup from old style dexron fluid. I personally think dexron3/mercon is best. Perhaps syn. fluid lubricates better, but we have NEVER seen lubrication related hard parts failure, other than differentials. There is no A.T.F. that can solve that. Better lubrication qualities are not better for clutches that are supposed to provide friction IN MY OPINION. Hope this helps.
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