Synthetic ATF benefits are many for forks and primaries and there's zero negatives for using this fluid.
It's viscosity of 10w puts it right in the hunt for fork oils. Additives to control heat and swell seals makes it perfect to use in forks and primary. There are several ATF viscosities out there, the fluid has to service everything from regular autoboxes to heavy duty transmissions in big rigs both auto and manual.
So yes it has lubricity for the ramps chains sprockets bearings and seals. Perfect for wet clutches, cleans friction discs and keeps plates from overheating. Which is exactly the fluid's job in the primary.
Got leaks? Red color helps determine where the leak is or isn't coming from.
Been using atf in the Glide's primary since I changed her clutch (90,000kms). I'm approaching 220,000kms.
Less clutch adjustments, clutch feels meaty, solid, no slippage, no clunking, easy N find on cold starts.
Best fluid to use in your primary. My opinion..

 

Years ago, I put a primo rivera extra disk in my former softail and it listed B&M trickshift as recommended for their clutch pack in the instructions.

Lubricity...
you must be a Tribologist

 

I hope this is not thread drift but a well known engine builder occasionally would do a build job for someone who would cheap out and not spring ( pun intended) for a heavy duty clutch springs.

When the customer would complain of slippage he would put in ATF fluid. It would correct the problem as it would squeeze out from the discs faster thereby improving the plates gripping better. After all it is designed for the CLUTCHES in automatic transmissions.

 

Nah....Canadian