These transmissions do not just "slip". The Transmission Control Module (TCM) constantly monitors Turbine Shaft Speed (TSS) and Output Shaft Speed (OSS). If there is an unexpected variance between the two, it sets a DTC and Check Engine Light (CEL) immediately. Possibly even a Wrench Lamp.
Ford released a revised calibration for 2017 and 2018 (mid-year) models with the 10R80 transmission for various engagement and shifting concerns. If you have a vehicle within this build date range, I would suggest having the update applied.
TECHNICAL SERVICE BULLETIN 18-2274
2.7L/3.5L/5.0L Engine And 10R80 Transmission - Harsh/Bumpy Shift And/Or Engagement Concerns - Built On Or Before 15-May-2018
07 September 2018
Model:
Ford
2018 F-150
Issue: Some 2018 F-150 vehicles equipped with a 2.7L, 3.5L or 5.0L engine and 10R80 automatic transmission and built on or before 15-May 2018 may exhibit harsh/bumpy upshift, downshift and/or engagement concerns.
Action: Follow the Service Procedure steps to correct the condition.
Warranty Status: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage Warranty/ESP coverage limits/policies/prior approvals are not altered by a TSB. Warranty/ESP coverage limits are determined by the identified causal part and verified using the OASIS part coverage tool.
Description Operation No. Time
2018 F-150 2.7L/3.5L/5.0L: Reprogram The PCM (Do Not Use With Any Other Labor Operations) 182274A 0.3 Hrs.