Sub-Compact Gear Driven Tiller Series 923 Get more work out of your sub-compact tractor with Taylor Pittsburgh's Sub Compact Gear Driven Tiller. The 923-GDT-48 (48”),for sub compact tractors up to 25 horse power and the 923-GDT-54 (54”) for small compact & large sub-compact tractors up to 35 horse power,both have all the quality features of the full size tillers. The heavy duty frame and six tines per flange produce a better seedbed. A slip clutch PTO shaft transfer’s power smoothly to the Gear Driven center and side gearboxes