Small Engines (Lawn Mowers, etc.): Self Propel Drive locking up on Sears Craftsman Lawnmower, sears craftsman lawnmower, driving wheels

Question
I have a Sears Craftsman lawnmower that is supposed to be self-propelled.  It's the sucky model!  Everyweek I have to fix something on it.  This week it busted and threw the self-propeller belt and I replaced it from Sears.  After replacing the belt (I made sure no remaining pieces were there)I checked the tension and it seems OK.  The wire/cable is pulling back on it and the wheel for the belt is lifting.  BUT... when I have it started and pull back the handle to engage the self-propel feature it totally locks up the wheels and I can't even push it forward myself when engaged. Any thing to check or is there a locking mechanism that I can't see?  The parts by the front wheels are all enclosed and I'm not sure what to expect if I open the box.  Any suggestions or instructions that are understandable would be appreciated.


Answer
When the wheels lock up the belt stopped turning?  If so there is a problem inside the transmission or the wheel drive system.  Work your way inside first remove the driving wheels.  Inspect the gears inside the wheels.  Next remove the wheel drive system and inspect the parts.  If that is not it remove the transmission and see if you can operate it manually.

Typically self-propelled lawnmowers will not push easily when the drive is engaged.  Usually the drive cannot be engaged to easily push the mower.  There is usually a wheel drive drives in one direction this means that there is a left side and the right side to the drive system.  If any of this was removed to replace the belt you have to get it back the way it was.  If you are purchasing parts from Sears go to Sears parts direct.com and put your model number in on the right-hand side of the page.  You should be able to bring up and exploded view of your mower.  This would be a good guide to show you how it goes together.  The other thing would be to purchase a service manual directly from Sears.  I hope this helps