The sealing rings are synthetic resin with chamfered ends. Check the condition of the sealing rings, and replace them only if they are worn, distorted, or damaged.
For a better fit, squeeze sealing rings together slightly before installing them.

Apply ATF to the new sealing rings, then install them on the secondary shaft.

After installing the sealing rings, verify the following:
The rings are fully seated in the groove.
The rings are not twisted.
The chamfered ends of the rings are properly joined.
Driving
This chapter discusses driving, refueling, and information on items such as
accessories. ...
Service Station Procedures
Refueling
1. Park with the driver’s side closest to the service station pump.
2. Outside of the vehicle, open the fuel fill door by pulling its notched edge.
3. Remove the fuel fill cap slowly. ...
Rocker Arm and Shaft Disassembly/Reassembly
NOTE:
Identify each part as it is removed so that each item can be reinstalled
in its original location.
Inspect the rocker arm shaft and the rocker arms.
If reused, the ...