Remove the fill plug  and the drain plug  to drain the oil from the unit.
Remove the coupling access port  and use a 1.5mm hex  to loosen the motor coupler. You may need to handle jog the rotary to get the coupler screw into alignment with the hole.
Remove the (4) adapter port covers  and use a 5/64 hex to remove the (4) set screws  holding the adapter onto the HA5C nose.
Using a strap wrench  unscrew the HA5C adapter/5th axis from the HA5C nose.
Remove the (7) 1/4-20 bolts .
Separate the adapter  from the 5th axis and remove the inner O-ring .
Note: The 5th axis is a tight fit to the adapter. If stuck you can use the 1/4-20 jack bolt hole  if equipped or thread the adapter back onto the HA5C and lightly tap the 5th axis with a mallet to separate the two pieces. Do not let the transmission shaft fall or come out.
Install the adapter and torque the bolts  to 12 ft-lbs.
If equipped with the jack screw hole install the 1/4-20 plug bolt  and copper sealing washer, 40-1631 & 49-4101.
Make sure the transmission shaft did not rotate so the coupler  is still aligned with the access port.
Remove the cross pin access cover . Insert a 3/16 cross pin, or 3/16 drill bit , into the hole. It will sit just under the motor shaft and will push against the coupler to set the preload of the transmission shaft.
Thread the 5th axis assembly onto the HA5C nose. Use care to get the transmission shaft  piloted back onto the motor shaft.
Tighten the (4) set screws  on the adapter. Install the (4) access cover plugs .
Tighten the motor coupling bolt and install the access cover.
Note: If the motor coupler is no longer aligned you can remove the front cap  and rotate the worm gear to correct the alignment.
Remove the cross pin, or drill bit. Leave the access plug out to refill with oil.
Install the drain and fill plugs.
To fill the unit with oil, SHC 627, rotate the tilt axis up 30 degrees.
Add oil to the 5th axis body  until oil comes out of the bottom port on the motor mount . Install the plugs.
Rotate the platter two full turns in both directions to allow the oil to run through the unit.