[wakespeak]

AC Delco makes 2 transmission products: synchromesh 88900333 and manual transmission and transfer case fluid 88861800. 88861800 is specified for the tr6060 not synchromesh.

I think for manual transmissions you have to consider 2 things : lubricating the metal parts and having the right friction characteristics for the synchronizers to work well and live a long time. Most atf products are "friction modified" to allow the clutches to engage properly. The tr6060 makes some assumptions like this for the synchronizers.

Redline probably adds friction modifiers to its products but I don't know how compatible those are with the materials Tremec is using for the synchronizers. It may work great, but wear out the synchronizers faster. The reason I am pointing that out is that even within the various atf's friction modifiers vary a lot. Don't go putting Dexron in a Chrysler transmission for instance. Whether the tr6060 is that sensitive to say d4 to a mix with mtl to gm stock fluid just not sure, but I have taken the middle in my mind with a synthetic atf.