Ok good it is working.
The time may be missing for two reasons. Is the timestamp written after the 128th character in the event (which is the default of the parameter MAX_TIMESTAMP_LOOKAHEAD). Increase the MAX_TIMESTAMP_LOOKAHEAD if it is the case.
More, to make sure timestamp is recognised by Splunk, use the TIME_FORMAT parameter in the sourcetype definition (below the TRANSFORMS-sourcetype = sourcetypechange).
TIME_FORMAT=%b %d %H:%M:%S
For info on how the time variables work, http://docs.splunk.com/Documentation/Splunk/7.0.2/SearchReference/Commontimeformatvariables
TIME_FORMAT = <strptime-style format>
* Specifies a strptime format string to extract the date.
* strptime is an industry standard for designating time formats.
* For more information on strptime, see "Configure timestamp recognition" in
the online documentation.
* TIME_FORMAT starts reading after the TIME_PREFIX. If both are specified,
the TIME_PREFIX regex must match up to and including the character before
the TIME_FORMAT date.
* For good results, the <strptime-style format> should describe the day of
the year and the time of day.
* Defaults to empty.
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