Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

The differential knob on the used  ST824 I recently purchased is stuck in the locked position. The knob won't pull out. I sprayed around it with WD40 yesterday and am letting it soak in. If I have to use a crowbar to get it to pull out will it damage the differential? Also, The machine is equipped with tire chains, and my driveway is very flat, do I really need them? It is difficult to turn with them. On my previous snowblower I never needed chains? Your help is appreciated.

Mike