interesting - Now all is required that we show him a Ducati desmodromic valve train - it has no valve springs and the tappet gaps are set to 0.0mm
(lets see him find a 0.0mm feeler) - too loose and the valve clatter is deafening, too tight and the cylinder compression goes to zero.
Its EFI and 4 valve/cyl too.
btw - trans not shifting to D4 is usually 2 cases
1 shift cable is not correct
2 engine is not warmed up.
3 sticky solenoid (D4 lamp flashes)
you are screwed case is
shot clutch pack
bad regulator valve in pressure control valve body.