On my Toro Model 20332 (my 2011) the pivot arm #108-9781 was similarly toed in. This created a partial separation between the gears causing eventual wear of the original plastic gear and IMMEDIATE stripping of the plastic gear on a brand new wheel #138-3216. Over the course of 12 years use it seems that the pivot arm bent inward (towards the engine). Replacement of the pivot arm would've solved the problem. Instead I inserted a pry bar between the pivot arm and the mower deck and gently pried the pivot arm straight. I also replaced the stepped washer #614426 at this point as the original was badly worn. When the gears meshed properly the gear stripping issue was resolved. The check for proper gear mesh is to support the mower deck with rear wheels raised and spin the rear wheels forwards and backwards by hand. If the rear wheels rotate smoothly without binding or checking in each direction, the gears are meshed and correctly aligned.