SlickWilly, here's a photo of that bracket on a transmission I found on ebay: http://www.ebay.com/itm/Cub-Cadet-1250-Tractor-Transaxle-Transmission-Assembly-/190788238705?pt=LH_DefaultDomain_0&hash=item2c6bdd7d71
Look in the upper right hand corner of the photo and you'll see a rectangular bracket. This is the bracket that gets worn and causes the transmission to do things it isn't supposed to do.
Here's yet another and you can actually see the spring. http://www.ebay.com/itm/Cub-Cadet-106-garden-tractor-Transmission-Hydrostatic-Pump-/290929972345?pt=LH_DefaultDomain_0&hash=item43bcc71479
Hope this helps some.