Honda Pioneer 1000 2017 Owner's Manual page 147

Refer to Safety Precautions on page 123.
The front seat must be removed, to check the sub-transmission oil,
to add the sub-transmission oil and for throttle cable adjustment.
Removal
1. Open the doors (page 54).
2. Pull the seat lock lever at the front center of the seat.
3. Pull the front of the front seat upward then slide it slightly
forward.
seat lock lever
prongs
Installation
1. Insert the hooks into the frame and the prongs into the
grommets of the front seat.
2. Press down on the front seat until it locks.
grommets
front seat
hooks