By TMZ

They've trashed each other for YEARS -- but WBC heavyweight champion Deontay Wilder (37-0, 36KOs) is putting his feud with Tyson Fury (25-0, 18KOs), the IBF/IBO/WBA heavyweight champion, on immediate hold ... saying he truly wants Fury to get help for his cocaine problem so he doesn't die.

Wilder says he was really impacted when he learned about Fury's drug problem and suicidal thoughts -- and says he's even willing to fly to England to lend his support to his embattled rival.

That being said, Wilder still wants to beat the hell out of him ... saying, "We didn’t promote [a possible fight] this many years to be beat behind some kind of drug activity."

Fury, citing mental issues, withdrew from a planned October 29th rematch with Wladimir Klitschko. It was later revealed that he tested positive for cocaine in two separate drug tests that were issued by VADA.

Then last week, in an interview conducted with Rolling Stone Magazine, Fury admitted to using high volumes of cocaine, abusing alcohol, and having suicidal thoughts.

Given Fury's issues, Wilder is not happy with the army of critics who are slamming the troubled fighter on social media. Wilder is willing to bail on his current rehab, for injuries suffered during his July knockout of Chris Arreola, to fly over to the UK to provide support to Fury.

"Bring this man up, instead of negativity to bring a person down. Now I hear him talk about suicidal thoughts and things like that. When you have so many people say things, especially when you do something, and it goes viral around the world - its too much for one person. That's a lot of batter, a lot of negative come your way. I don't think its right. He has to lift his head up and stay strong," Wilder said.

"If I have to go see the man, I will take a trip to England. I'll put aside what I have with rehab and stuff like that. I will definitely put it aside for a life. My arm is healing, but we cant get back a life. He really is a good dude, outside of what people see of him, what he do to promote a fight. He do what he has to do to provide for his family."

Fury and Wilder went face to face during a wild scene back in January, when the British boxer was ringside at Brooklyn's Barclays center to watch Wilder drill Artur Szpilka.