A removable teeter lever and gear assembly arrangement for use with a pneumatic cylinder/differential engine for operating vehicle doors, said arrangement comprising: (a) a housing, a gear assembly comprising a gear having an output shaft extending therethrough, said gear and a portion of said output shaft disposed within the housing, a teeter lever mounted on a portion of said output shaft disposed outside of the housing, wherein rotational movement of said output shaft and said teeter lever is caused by actuation of said pneumatic cylinder/differential engine; (b) said teeter lever being associated with said vehicle doors such that rotation of said teeter lever causes opening and closing of said vehicle doors; said arrangement being characterized in that: (c) said teeter lever includes a first aperture and said output shaft includes a second aperture, said first and second apertures being aligned and extending along a longitudinal axis of said output shaft, an axial securing member extending through said first and second apertures and preventing axial movement of said teeter lever with respect to said output shaft, and in that it comprises: (d) angular securing members removably securing said teeter lever to said output shaft and said gear to said output shaft, such that said teeter lever and said gear are not able to rotate relative to said output shaft, said angular securing members comprising a first retention key cooperating with said gear and a first keyway formed within said output shaft for removably connecting said gear to said output shaft and a second retention key cooperating with said teeter lever and a second keyway formed within said output shaft or removably connecting said teeter lever to said output shaft, and (e) a first pair of retaining rings (21a, 21b) each positioned on a respective side of said gear to limit axial movement of said gear relative to said output shaft and a second pair of retaining rings (25a, 25b) each positioned on a respective side of said housing to prevent axial movement of said output shaft with respect to said housing. (a) a housing, a gear assembly comprising a gear having an output shaft extending therethrough, said gear and a portion of said output shaft disposed within the housing, a teeter lever mounted on a portion of said output shaft disposed outside of the housing, wherein rotational movement of said output shaft and said teeter lever is caused by actuation of said pneumatic cylinder/differential engine; (b) said teeter lever being associated with said vehicle doors such that rotation of said teeter lever causes opening and closing of said vehicle doors; said arrangement being characterized in that: (c) said teeter lever includes a first aperture and said output shaft includes a second aperture, said first and second apertures being aligned and extending along a longitudinal axis of said output shaft, an axial securing member extending through said first and second apertures and preventing axial movement of said teeter lever with respect to said output shaft, and in that it comprises: (d) angular securing members removably securing said teeter lever to said output shaft and said gear to said output shaft, such that said teeter lever and said gear are not able to rotate relative to said output shaft, said angular securing members comprising a first retention key cooperating with said gear and a first keyway formed within said output shaft for removably connecting said gear to said output shaft and a second retention key cooperating with said teeter lever and a second keyway formed within said output shaft or removably connecting said teeter lever to said output shaft, and (e) a first pair of retaining rings (21a, 21b) each positioned on a respective side of said gear to limit axial movement of said gear relative to said output shaft and a second pair of retaining rings (25a, 25b) each positioned on a respective side of said housing to prevent axial movement of said output shaft with respect to said housing.