Tail gate torsion rod?

[ocelot3454]

My tailgate has become very heavy over night. I assume The torsion rod has failed. The hinge pivot on the drivers side was making a loud snapping sound but that stopped when the tailgate became heavy.
Can anyone tell me what the correct name for this part is and can I replace it or do I need to take it to the Dealer?
Thanks

 

[jljbtm]

It might not be a spring at all it might be a torsion rod and I wonder if they are adjustable?

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