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.
Manual Transmission
Release the parking brake.
Shift the transmission to neutral.
Leave the ignition switch in ACCESSORY (I) so the steering wheel does not
lock.
Make sure all accessories ar ...
Replacement (Part -1)
Remove some of the brake fluid from the master cylinder.
Raise and support the vehicle.
Remove the front wheels.
Remove the brake hose mounting bolt (A).
...
Change Lever Clearance Inspection (M/T)
Measure the clearance between the change lever (A) and the select lever
(B) with a feeler gauge (C). If the clearance is more than the service
limit, go to step 2.
...