Not Starting, Yikes
 

MY 300D is not starting on the cold mornings but it starts great every other time. I have to pull around the Jeep and jump it off on the mornings that get to around 30 degrees. I cleaned the battery terminals and that helped a little. It starts right up w/ a little help from the Jeep.

I have been told that it might be the alternator.. Is that true??

Could be the alternator or could be a bad battery. Put a multi-meter on the battery with the engine running to check the voltage. Should be high 13's or 14 volts. If it's less than 13 (.6?) then alternator or voltage regulator is bad. If voltage is ok, probably got a bad battery.
Do you have a group 49 battery? Diesels need a lot of oomph to start in the cold.

How can I tell if I have a group 49 battery? I have not changed the battery yet.
What setting should I have the volt multimeter on??? I have a hard time understanding how to work it??