So, I was reading reading a piece about the creeper drive unit, not that I'm installing one. There is much mention of gear oils, using lighter weight stuff rather than SAE 90. The trans on my Elec-Trak had 4 speeds including L and LL (creeper gear for ground engaging eqm like a moldboard plow and rototiller) - the electric drive motor powered the trans using two belts. Simple and very workable. The double sheave pulleys on motor and trans could be changed to alter speed. A friend built these tractors and only used SAE 50 Racing Oil in the trans. Just sayin.'