Hey Scotty, I have a 05 GMC Sierra 2500HD with 112,000 miles on it and a 5 speed automatic transmission, I was wondering when or if it should change my transmission fluid, it has not yet been changed thanks.
Clarification: How does the fluid look and is it shifting fine?
Shifts fine still smooth no bumps
Really depends on what the fluid looks like and what @daywalker said. If its not burnt smelling or black. I’d do a drain and fill.