There is a screw & loc-nut down on the side of the gearbox. You may be able to lessen the "play" by loosening the nut & running the screw in. Don't forget to tighten the loc-nut when your done.
During the purchase of my used BX2200 I noticed a "wander" as well. The dealer advised me they replaced a seal in the power steering that was allowing power steering fluide to pass through (...something), and that fixed it.
This system is similar to the Grand L xx30 series and others. There was a well known problem with a group of BX cylinders being bad and having to replace seals in them.
David Kb7uns