Craftsman 203901 Drive Problem

I have a T3000 model 203901 that will not go from forward to reverse or vice versa without pressing the brake pedal. Once in gear it will not stop unless the brake is pressed. The brake is essentially a clutch at this point. Any ideas as to what might be the problem? The linkages and springs appear to be in tact. There is some grease coming out one of the rear axle seals that may or may not be related. I'm literally one day out of my two year warranty! Thanks for any suggestions.

Found a post by Boobala from 6/10/17 with links to some great resources on the transmission used in this mower. I dropped the tranny and it looks like I need to clean the variation unit. Will probably install the debris sealing kit while I'm at it and take care of the axle seal. Thanks for the info.