I have switched to Transynd fluid in all my stuff. BEen running it for a couple of years and still looks new. It is the Allison trans fluid used in Medium trucks, motohomes etc.
Application
Castrol TranSynd can be recommended for all vehicles calling for Dexron III/Mercon or Allison TES 295 and TES 468 ATF's
suitable for bus and refuse vehicles with automatic transmissions.
Garbage trucks?
That TranSynd is about $50 /gal. Almost triple the cost of Dexron III/Mercon that it replaces. Does it say B&M Trick Shift on it?