Trouble with garage door opener

[cabinetman]

It might be a planned engineering decision to make the gear the weakest point (e.g. a mechanical fuse) so that a jam and a failed force limiter won't pull down the garage structure.
I can't really say.

Could be.

.

[Turaj]

Update

So after checking the availability of the parts and prices, ended up ordering the complete replacement kit for $25 from Sears Canada plus $10 shipping (Sears selling the gear alone for $23 so it was an easy decision to go with the full kit).

The package arrived while I was away and sat in the garage for over 5 weeks until I finally had a chance to put the new parts in. It took me about 45 minutes to install the gear and make all the adjustments (really off on travel up and down) but all is back to normal now.

BTW, I also found bunch of videos that gave a lot of visual help in knowing what to expect. Thanks for all the help pointing me in the right direction.