In order to change the suspension fork, you will need to remove the entire drive.
Start by removing the transmission only... and reinstall the transmission last when going back together.
This opens up the area for shift cable clamp access, and water neck fitting access.
Next.... use heat on the aluminum hinge pin bosses at the transom shield to expand the material some.
Drive the hinge pins outward with a soft brass or aluminum punch as to not expand the hinge pins.
Once off and in your work area, remove the lower unit.
Now you will gently and carefully press or drive the pivot tube downwards and out.
The tube is mildly friction fit within the Intermedaite housing, and if corroded at all you may want to heat this area.
The pivot tube also is rather soft, so be careful that you don't damage either end of it.
The upper area seals against a beaded gasket, and the lower area seals against an o-ring.
Look at the pivot tube needle bearing surface for any signs of rust damage.
Note the two white nylon spacers at top and bottom of the reverse latch bearing sleeve and the SS wear washer locations.
I would replace the pivot tube lower needle bearing/seals and the upper bushing while in there.
You'll want to also hand pack the needle cage because Volvo Penta did a lousy job with the grease porting here. The needle cage should have been ported and lined up with the port in the suspension fork.... but they screwed up.