Lawnboy Gold Series Self Propelled not working under load

[zatoholmes]

The self-propelled feature on my Lawn-Boy Gold Series Model 10655 seems to have stopped working. I replaced the gears in the wheels but it still doesn't work under load when place on the grass and especially when going up hill. When the rear wheels are lifted off the ground, they do spin. Anyone have any ideas what I should look at next?

Divorced and figuring this out on my own!!

 

[Rivets]

I would replace the belt if it has not been done in the last three years.

 

[Rivets]

Sorry forgot to tell you. Part number 91-2258