are they all 6 speed after 2015
just trying to work out what box it is
if VMT6
i started looking on the net for common stuff on them .. and AI gave mere all this .. and just about says it all and saved me a lot of typing .

couldnt put it any better myself
When a VMT6 transmission "jumps out of gear," the cause is usually related to worn internal components, gear selection mechanisms, or engine/transmission mounts.
Common Causes and DiagnosisThe most frequent causes for a manual transmission popping out of gear involve wear and tear over time:
Worn Internal Components: This is the most common issue.
Detent Springs and Balls: These small components hold the gear selector rails in place. If the springs are weak or broken, the gear may not be held in full engagement and can easily slip out.
Worn Gears and Synchros: The teeth and "dogs" that lock the gears together can wear down over time. When worn, they no longer mesh correctly, allowing the gear to disengage, especially under acceleration or deceleration.
Worn Selector Forks: The forks that move the gears inside the transmission can become worn, preventing them from pushing the gear into full mesh.
Gear Selector Mechanism/Linkage: well you are on to that
Misalignment or Damage: Problems with the external linkage, such as a bent connection rod or worn bushings/clips at the base of the shifter, can prevent the gear from being fully engaged.
Poor Adjustment: If new gear selector cables were recently installed, poor adjustment could cause poor selection and the gear to pop out.
Engine/Transmission Mounts:Worn Mounts: Excessive movement of the engine and transmission due to worn-out mounts (especially the rear stabilizer on some models) can pull on the gear selector mechanism, causing it to pop out of gear.
Driving Habits:Resting Your Hand on the Gear Stick: This habit can put excessive, constant pressure on the selector fork, leading to premature wear of the internal components.
The cables not mentioned though.. you know i would not think they are the trouble .. you'd have difficulty getting it into gear if that was so .. but you can oil them .. and if you ever do any external oiling on a car or van always use gear oil or machine oil, as engine oil is sort of makes things rust .. as it absorbs water ... there are gadgets and gizmos for oiling cables .. but you buy these if you have old
vintage cars/ motor bikes with no nylon liners in the cables. i always done it with plastic cut-up 500ml coke bottles taped into place.
but engine / gearbox mounts .. shaking about could pull it out of gear .. that's the first check i think
just note .. to get a high gearbox mileage .. oil should have been changed every 50,000 miles (ford says never)
all the best.mark