The Commodores -- Getting Our Name Back Isn't Easy

The Commodores have commandeered their name back ... from an ex-member who tried to jack it.

A judge has decided founding member Thomas McClary relinquished his right to the Commodores brand 30 years ago when he left the group.

As we first reported ... the remaining members of the Commodores sued McClary in August claiming he illegally hijacked their name -- touring as "The Commodores featuring Thomas McClary."

For what it's worth ... there will be a full-blown hearing later, so the judge could change his mind.