Dexron III or Synchromesh for T45? Anybody tried both in short period of time?

[Speeds8erM-1]

I have searched and searched, and ended up in alot of OLD posts from like 03-04, where there seemed to be alot of confusion, plus people throwing in their two cents about 3650's, which really doesnt help.

Which fluid is better for a T45, Dexron III (which seems to be hard to find now with all of the Mercon V & VII stuff now) or Synchromesh? Anybody ever switched from one to the other in a short period of time for comparison?

The person I bought my 98 GT from says he put synthetic in it, which seems like a big no no in the T45, from what I have read. Im wondering if it maybe it will shift a little better with something else?

Im swapping the clutch soon, figure this would be as good of a time as any

 

[squeak93]

Synthetic is bad on t45's b/c of the paper material on the syncro's. I use dex III in mine. Seems to be a bit less testy than with the synthetic that was in it, but I have 150k of HARD miles so I expect it to grind when power shifted.