Johnny Drama ... err, Kevin Dillon -- best known for his role on the hit HBO show "Entourage" -- says he's hauling in way less moolah these days, so he can't fork over any more to his wife ... according to new legal docs.
Kevin just disclosed his current income in connection with his estranged wife's request for him to pay her lawyer's fees in their ongoing divorce case.
Dillon claims he's making $4,000 a month ... clearly way less than he made while he filmed his hit TV show.
He says in his papers he's already paying her more than $10k a month in spousal and child support, so he's tapped out.
He and Jane Stuart are also bickering over who pays for 12-year-old daughter Ava's private school.
Kevin does say money is on the horizon. They own a home with more than a million bucks in equity, which will soon be divided between them.