GM Sinchromesh and T-5

[jimberg]

This is taken directly from the TTC web site.

What type of lube is recommended for my TREMEC transmission?

The following types of lube are recommended:
TR-3550/TKO - GM Synchromesh or Dextron III
TR-3650/T-45/T-5 - Dextron III
T-56 (Ford and GM) - Dextron III
T-56 (Viper only) - Castrol Syntorque

GM Synchromesh is too heavy of an oil to use in a T5. I don't think you would benefit at all from using it, so, yes, looking at Red Line would be a better alternative.