The maximum number of "real" seconds that can be used for a timeout value (calculated) for a JOB/STEP is 65533, or approximately 18.2 hours. If the time as calculated exceeds 65533 seconds, then a JES000034E message, as shown below, is issued to the console and the maximum value of 65533 seconds is applied to the job.
JES000034E JOB10348 - TIME parameter exceeds 65533 after applying class multiplier (0100)