Try checking the drive belt. It's tucked up under the mower and not the same thing as the lower belt that drives the blades. Also, check if both rear wheels are turning, as the shear pin where the wheel attaches to the axle may be worn or missing.
Craftsman LT1000 Owner
May 2005
I can answer this question...
Why My Craftsman LT1000 want pull up a small hill? It jerk then stop?