Chumlee's relationship with Richard Harrison spanned about 20 years, and he has a lot of fond memories of the man they called "Old Man" ... and some funny ones too.
The "Pawn Stars" star tells "TMZ Live" ... even though "Old Man" wasn't truly his family, he was always treated like a grandson and he learned many life lessons from him.
Chumlee says he's happy he got to spend some time with Harrison in recent weeks as he battled Parkinson's Disease and, while he was prepared for the inevitable, it was still a surprise when he died ... because "Old Man" always fought like hell.
Chumlee tells us the outpouring of love for the "Pawn Stars" patriarch has been incredible, and he shared his favorite memory -- taking "Old Man" for a ride in his lowrider, and giving him a surprise hydraulics lesson.
As we told you, the famed Gold & Silver shop in Vegas created a memorial to honor Richard, and it's been flooded by fans paying their respects.