Tuffcut 220, 12AD566N063
Front wheel drive has stopped working. The gear to the right wheel is froze up and will not remove after removing the O ring.
1. Can this be the reason the front wheel drive has stopped working?
2. Is there a solution to removing the gear? A special tool perhaps?

Hi,
You will need to spray with something to free it up. I would suggest one of the nonflammable sprays such as NutCracker, etc. They are expensive, but they work well.
Generally, the gear frozen to the shaft will make pulling the mower backwards difficult. It does not affect the driving, just the disengaging.
Your manual is available here:
PDF Manual Web Archive (http://manuals.mtdproducts.com/mtd/Public.do)
Just use a "1" as the serial number if you do not have it handy. Fairly large file of over 4.5 MB, so be prepared.
Peace,
Clarke

The gear (part 51 on the diagram in the manual) is frozen to the horizontal drive shaft. I have already replaced the left hand gear. Have used WD-40 and Naval Jelly on the bad bear. Still unable to remove it.

The original problem I was having was the front-wheel drive stopped working. It appears that the right front wheel is frozen in place (unable to turn). After reading what you wrote, my problem might not be the gear after all.

Any suggestions?

Thanks

Hi,
Yes, normally a frozen gear will prevent rearward movement. Check belt tension and turn the input sheave by hand with the drive engaged while watching the gears (wheel off) to check for transmission operation.
Peace,
Clarke