My 925A2 was stuck in 4' of mud, and the winch sucked it right out, didn't even need to snatch double the line. This was all in neutral. I was also wondering if the drive wheels can help out, but I forgot to check while doing so, and just did it all in neutral.
Reminder: Don't operate the hydraulic pump over 1800rpm as stated in the manual. I did not know this, and I held the pedal on the floor at about 2300rpm to wind the winch and get out, and now I have a medium size hydro leak at the direction control valve. If you compare the inlet and return hydraulic line sizes, you can see why they want you to limit to RPM (flow). The hydraulic pump can out-flow the control valve and the pressure relief within it.
Also I think you may have your PTO engagement procedure backwards. Trans goes into Drive to engage PTO (pump), then put trans into Neutral to spin the PTO (pump). It is opposite of how you think it should work, because it is an automatic and the gear case contents are all at a standstill when in Drive when not moving.