Tremec Question

Which tremec?? They do make more than one. The Tremec T-5 takes ATF, while the older 3550's took GM Synchromesh. The new TKO's take either ATF or Synchromesh.

Everything else in Tremec's lineup takes ATF. Only the original 3550 was called out as taking synchromesh
 
Yeah.. I forgot about that..

This tranny is only a T5 Tremec.. So that would only be ATF..

I was told by Tremec that a Synthetic ATF would be a bad idea? Is that true?