According to a leaked internal email obtained by Business Insider on Thursday, Tesla's delivery department is "facing a significant shortage of volunteers" for the final weeks of the year.

"If you are able to help, please sign up," Bert Bruggeman, Tesla's head of manufacturing, wrote to employees in the email.

The pressure apparently came from the top. According to another leaked email earlier this month, Tesla CEO Elon Musk had made delivering cars to customers and increasing solar product installation rate the two top priorities before the year ends.

This isn't the first time Tesla has turned to extra labor to fulfill period-end orders. Six months ago, before the end of Tesla's second fiscal quarter, a group of loyal Tesla customers formed a global special task force to help the company sell as many cars as possible to meet its quarterly sales target.