From page 419 of the owners manual for the 2012 F-150;
https://www.fleet.ford.com/maintenan...ls/results.asp
TRANSMISSION FLUID
Checking 6-speed automatic transmission fluid
The automatic transmission does not have a transmission fluid dipstick.
Refer to your scheduled maintenance information for scheduled
intervals for fluid checks and changes. Your transmission does not
consume fluid. However, the fluid level should be checked if the
transmission is not working properly, (i.e., if the transmission slips or
shifts slowly) or if you notice some sign of fluid leakage.
Transmission fluid should be checked by an authorized dealer. If
required, fluid should be added by an authorized dealer.
Do not use supplemental transmission fluid additives, treatments or
cleaning agents. The use of these materials may affect transmission
operation and result in damage to internal transmission components.
