I have a toro self-propelled 20017 mower[almost 3+ yrs old] and it has suddenly stoped self-propelling. The engine starts without any problems.
It takes a lot of strength to move the mower.
I heard a loud pop before it stopped working. Blade is ok.
I will start working on it tomorrow, will check the belt first.
Is there anything else I should be looking at?

Thank you for your help.