Suzuki DF 40 Service Manual page 237

9-3 LOWER UNIT
To separate the bearing housing from the gearcase, use two
(2) 8mm bolts as screw jacks, by alternately turning each
one equally.
This will keep the housing level as it pushed off the gearcase.
Remove the pinion gear .
Remove the forward gear (with thrust washer , back-up
shim and bearing )
Lift out driveshaft , driveshaft bearing housing and shift
rod assembly .
Account for the seal on the driveshaft bearing housing.
Remove the detent ball , spring and plate .
Shift cam
Remove driveshaft from driveshaft bearing housing and
take off shim , thrust washer and thrust bearing .
Pull out the spring pin , then remove the preload spring .