Absolutely have to remove it from the tractor. Take pictures as you take it apart. There are several things that are possible to be assembled wrong if you are not careful. Also take note that there is one of the large O-rings that is slightly different size than the others, and it goes in a specific place. There is a spring kit I'd also put in while you are in there. The seal kit and spring kit are both NLA from Cub Cadet, but there is a JD part number floating around somewhere that is still good.
I would not disassemble the metering package unless you are absolutely certain there is something wrong with that part. The tractor not steering correctly is more likely due to a worn charge pump in the hydro unit, worn/loose steering linkage parts, or a worn steering cylinder.
I've attached the service instructions for the steering column, which are better than the ones that are in the tractor's service manual, which is here:
http://ccmanuals.info/pdf/82-72 Series Chassis Manual.pdf