My understanding is that this Ford 6 speed transmission was originally tested at max load for 250K miles with only OEM recommended maintenance service performed. It was designed to outperform the Allison which GM uses in their comparable trucks. I have contact with Ford techs who tell me they have not seen failures in this transmission that were not low fluid related. It's success is probably due in part to it having a separate cooling system not tied to the engine cooling system. I have over 170K miles on mine and it performs like a new one. I followed the service recommendations and had cooling system flushed, axle lubricants changed, transfer case and transmission fluid exchanged at the 150K mile mark. The tech (a friend of mine) told me the transmission fluid was dirty but not burnt. This is obviously not the transmissions of old.
2011 F350 4x4 XL Crew Cab Dually
2010 Keystone Fuzion 405 Toyhauler
Last edited by badbart; 09-11-2018 at 05:29 PM.