gear lube??
This has been beat to death so much... that just explaining this to you... is also considered beat to death.
There are hours and hours of good technical input on this subject and none of us want to re-type everything there is for the eleventybillionth time.
In short, a straight weight 140... will let it live a little longer than something less.
You will most likely have some issues finding this, and I dont know why, but... my second choice would be the TORCO RGO 85-140. Its much easier to find than the straight weight oils.

