Pacer, 17.5 HP Walk-Behind Mower won't move by hand

[conservationman]

Pacer, 17.5 HP Walk-Behind Mower & 34 Mower Deck won't move by hand
5900630 Pacer, 17.5 HP Walk-Behind Mower & 34 Mower Deck
works fine with engine running but cannot push it by hand

the transmission release valve has no effect in either position
what can i do?

 

[enigma-2]

Pacer, 17.5 HP Walk-Behind Mower & 34 Mower Deck won't move by hand
5900630 Pacer, 17.5 HP Walk-Behind Mower & 34 Mower Deck
works fine with engine running but cannot push it by hand

the transmission release valve has no effect in either position
what can i do?

According to the manual:
Disengage the PTO, turn the ignition OFF, and
remove the key.
Slide the hydraulic release rod forward and lock
into the top of the "T" slot. See Figure 8.
Grasp the operator presence / parking brake
handles and the handle bar grips at the same time
to disengage the parking brake.
The mower can now be pushed by hand.
After moving the mower, re-engage the
transmission (DRIVE position) by releasing the rod
from the "T" and sliding the release handle towards
the rear of the machine.

If this doesn't work, either it's internal to the hydro or linkage has become miscaboomerated.