I have a Craftsman fs5500 lawn mower. It usually works great, however, recently, when it warms up, it will simply not pull of even slight grades. The motor runs well and strong, but the transmission will not pull the hill.

I do see oil that seems to be leaking so I'm wondering if there is a transmission lubricant of some sort that I need to change... and I suppose gaskets? Any advice on how best to diagnose the problem?
Any help would be great.

Thanks,
Phillip Thompson

If you have an oil leak it is very possible this is allowing the drive belt to slip. Clean or change the belt and the drive pulley but finding and repairing the leak is first.