Pull up -- am within range (5)
I believe the answer is:
gamut
'range' is the definition.
(gamut is a kind of range)
'pull up am within' is the wordplay.
'pull' becomes 'tug' (tug is a kind of pull**).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'within' is an insertion indicator.
'tug' backwards is 'gut'.
'gut' enclosing 'am' is 'GAMUT'.
(Other definitions for gamut that I've seen before include "Full extent" , "Ambit" , "Whole range (from A to Z)" , "Full (emotional) range" , "Full range, compass" .)