I read the Tremec installation guide and they recommend GM Synchromesh only. It's about $15 a qt. at the GM dealers. Then i found out that that
oil is manufactured by Pennzoil under contract and the PZ version is branded as Pennzoil Synchromesh @ $7.30/qt. TExaco also makes it for GM and markets it as Texaco T34 or something but I couldn't find it anywhere.
For the rear end, I've looked at various forums, including here, and the resounding recommendation seems to be
Amsoil Severe Gear 75W90 and adding the friction modifier. If you google "
oil for Ford differential", it kicks up various sites that discuss it. Redline and Royal Purple brands were mentioned also.
It's working great, so far.
