One of the reasons for using motor oil (20w-50 or 15w-40) and filling to 800-1000 ml was to help lube the sprag clutch assembly.
The sprag clutch assembly in the Bullet is the same one that is used in the torque converter of a Borg-Warner T350 automatic transmission. It normally spends its whole lifetime in ATF. Using ATF in our primary case won't have any adverse effects on its lubrication.
If i may chime in. I changed out my primary oil for 'F' type ATF 2 seasons ago and have not noticed any change. Maybe this is not typical but that is how i see it. This subject really doesn't need to be overthought,
just run what works best for you and use a full quart.Robert.
Hi Ace, Let me correct a typo for you please and thank you. The most common designator for the Borg-Warner automatic transmission that we are talking about is BW-35. T-350 is street slang around my area for GM's Turbo (Hydramatic) 350 Footnote: AMC used the BW-35 until the early 1970's and they were also wildly popular amongst almost every European car maker well after that.