[George Maz]

John, there four choices; Amsoil, Castrol, Redline, or ZF oil from Rockland Gear...they now own ZF. After my transmission was replaced due to "rare reverse spline lubrication failure" these were the recommended motor oils that must be used in our ZF transmissions, level checked, and changed at regular intervals.

I chose the Amsoil Manual Syncromesh 5w-30.
A thicker viscosity would dampen gear chatter noise for a lightweight flywheel, but I just wanted a thinner faster moving oil for guaranteed lubrication.

When filling, snake a hose from the top of the engine down to the fill hole, allow the excess to drip out from the fill plug hole till it settles, making sure car is level then insert plug. Trying to squeeze that extra love in there...winds up leaking out of the tailstock seal. 17mm stubby Allen impact socket if you need to borrow it.