I should be getting my ZF 5spd back from being rebuilt very soon. In the meantime, I have changed the seals in my pinion and axles. So now I am wondering if anyone has had any luck with Redline, or any of the fancy new synthetics for the trans & rear end? Or am I better off just sticking to the old tried & true fossil based lubes?
I have and been quite happy but do not fall into the trap of using GL5 in the transmission. If you research the backgrounds of the various GL ratings GL5 was designed for the needs of differentials, not transmissions and the chemistry is counterproductive to the needs and longevity of a transmission, especially one with brass syncros. Stay with a GL4 for the gearbox like one of Redlines GL4 MT series of lubricants and use the GL5 gear lube in the differential.
