The clutch pedal doesn’t spring back, esp. in reverse, esp. in reverse andor first gear.

Any ideas?

1999 F350 diesel dually/crew cab.

Since 1999 there has been plenty of time for lubricant to get dirty and corrosion to form at friction points in the clutch mechanism. I would check all those points and spray some lube in them at both ends, cab/firewall and at the trans. I don’t know what it looks like so I can not be more specific.