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.
Automatic Transmission
Shift Lever Position Indicators
These indicators on the instrument panel show which position the shift lever
is in.
The ‘‘D’’ indicator comes on for a few seconds when you turn the ignit ...
Connecting Rod and Crankshaft End Play Inspection
Remove the oil pump.
Measure the connecting rod end play with a feeler gauge (A) between the
connecting rod (B) and the crankshaft (C).
Connecting Rod End Play
...