Great points by alwayz_yummy... but singit ko lang something that namiss...

Check the contron cable.

There's a cable that links between the shifter and the tranny (kung san man yun papunta), pwedeng yun lang may sala.

Usually kung control cable or shifter bushing ang worn, mas kumakapit pag pataas ang shift (1 to 2, 2 to D, D to N, N to R, R to P) kesa pag pababa (P-R-N-D-2-1)...

In my case, may bushing lang na nagwear sa shifter mismo kaya may konting "play" yung shifter between gates... nothing to do with the tranny itself.