Product review (1 stars): KitchenAid or Whirlpool Dishwasher Top Rack Adjuster Repair
Do not recommend replacing this part.  The original design uses inferior plastic axel assemblies that fail and cause the top rack of the dishwasher to  drop out of proper position and jam.  The Whirlpool/Kitchenaid company offers a replacement kit for this assembly identified as W10712394 which provides all the parts to fix the top rack adjusters (both left and right sides are included in the kit along with retainer clips, etc).  The kit is available via Amazon  http://www.amazon.com/Whirlpool-0W10712394-W10712394-Adjuster-KIT/dp/B00SPYDSFC/ref=sr_1_3?ie=UTF8&qid=1423580463&sr=8-3&keywords=W10712394.  The instructions included with the kit are poorly written and illustrated, but a Youtube search for W10712394 will find a video that is more than adequate for a person with average mechanical skills.  Also, you will need a T15 torx screwdriver (not mentioned in the kit instructions), to secure the screws on the replacement assembly.