1996 Ford F-150 burnt clutch slipping / power loss

Hey guys I was trying to get my truck out of the driveway thismorning and I didnt seem to have to power to get out (driveway incline on the way out) the clutch seemed to be slipping and made that awful smell. It was in 4x4 and it also has 35 inch tires and an 8 inch lift on it. I have only noticed this problem in first and in snow or on a steep hill, but havnt payed attention to it in second +. Have only had the truck for a few days and just charged the batterie. Any thoughts if this is my clutch / flywheel and should I just get a new one or what? Also anything I should be doing to this truck since I just got it and not sure of the history? (Already topped all fluids and replaced trans fluid and transfer case fluid and oil change). Im also going to be attempthing clutch replacement myself and tips?