Kohler K91 Owner's Manual page 261

Charge Relief Valve
Remove the
5/8"
hex head
"0"
ring plug
(5,
Fig.
90).
Remove the spring
(1 1,
Fig. 91) and valve (12, Fig. 91)
using a magnet to withdraw them from the bore.
NOTE: There may
be
shims inside the plug to con-
trol valve spring tension. Take care not to lose them.
Remove and discard the
"0"
ring from the plug.
Check
the spring for distortion. Replace
if
damaged.
Check
the nose of the valve for continuous sealing
pattern and replace it
if
damaged.
Check
the seat in
the
center section for nicks or signs of erosion.
If
it
i s badly eroded, the Hydrogear assembly must
be
replaced.
Clean
the
parts with solvent and coat them with
type
"A"
automatic transmission fluid. Install a new
"0"
ring on the plug
(5,
Fig.
90)
using care not to
damage it on the screw threads. Install the spring in
the valve and insert the assembly, valve first, into
i t s bore on top of the center section. Install
the
hex
head
"0"
ring plug and tighten securely.
Towing Valve
(If
applicable)
Back out the
1"
hex shoulder plug
(6,
Fig.
90).
Pull
the valve assembly
(14,
Fig.
91)
out of the bore.
The
force required will depend on the radial press of
the sealing rings on the barrel of the valve.
Remove and discard the
"0" rings and the Teflon
back up ring
(13,
Fig.
91).
Clean the valve with
sol-
vent, dry, and coat with type "A" automatic trans-
mission fluid. Install
the
Teflon back up ring
(13,
Fig.
91) in the top groove of the valve. Install an " 0
ring alongside
the
back up ring in the same groove
on the side away from the valve stem. Install the
second
"0"
ring in the bottom groove. From top to
bottom of the valve, the rings stack up in this order:
Teflon ring,
"0"
ring,
" 0
ring.
Place
the
washer (15, Fig. 91) around the bore in
the
center section and, with a twisting motion, insert
the valve into
the
bore. Start the hex shoulder plug
threads and rotate the valve while drawing
it
into
place with the plug. Tighten
the
plug securely.
Implement Relief Valve (If
so
equipped)
Remove the
5/8"
hex head
"0"
ring plug
(7,
Fig.
90).
Remove the spring
(16,
Fig.
91)
and valve
(17,
Fig.
91)
using a magnet
to withdraw them from the bore.
Remove and discard
the "0"
ring from
the plug.
Check the
spring for distortion. Replace if damaged.
Check the nose of the valve for continuous sealing
pattern and replace
if
damaged.
Check
the seat in
the center section for nicks or signs of erosion.
If
it
i s
badly eroded, the Hydrogear assembly must
be
replaced.
Clean the parts with solvent and coat them with
type " A automatic transmission fluid. Install a new
"0'
ring on the plug (7, Fig. 90) using care not to
damage it on the screw threads. Insert the spring in
the valve and install the assembly, valve first, into
its bore on the front of the center section. Install the
hex head
"0"
ring plug and tighten securely.
Install :new oil filter. Install the drain plug in the
bottom of the transaxle.
Fill
to proper level with type
"A' automatic transmission fluid. Approximately four
quarts will
be
required.
Block the tractor up with the rear wheels off the
ground. Run the engine at low speed and operate
the Hydrogear in forward and reverse to circulate
fluid through the system and to check for leaks.
Recheck
the
fluid level and add as necessary.
Adjust neutral position. Lower rear wheels to the
ground. Reinstall the fender and tool box assembly.
Run the tractor to thoroughly test operation of the
Hydrogear.
HYDROGEAR
REMOVAL AND REPLACEMENT
Removal
If the
transmission has been contaminated either
with metal filings or other foreign matter, the fluid
must be changed and the oil filter replaced.
The
transaxle must also
be
flushed thoroughly before a
new Hydrogear assembly
i s
installed.
Support rear of tractor with rear wheels off the
floor. Remove the
left rear wheel. If
tractor has tail
light, disconnect wire and bring it forward of
the
tool box.
:If
the tractor has a hydraulic
lift,
disconnect
the hoses, from the Hydrogear and move them for-
ward out of
the
way. Remove the instruction plate
(located in front of the seat) by removing four mount-
ing screws.
Remove the four tool box to transmission bolts and
remove the fender, seat and tool box as an assembly.
NOTE: On
1965, 1966
and
1967
models it
is
also
necessary to remove the fan guard. The
1968
and
1969
models will also require the removal of the
two
belt
guard-to-tool box bolts.
Remove the
belt
guard and drive belt. To do this
on 1968 and 1969 models, the
R.H.
foot rest must
be removed. Remove the cooling fan from the drive
pulley, i f so equipped, and remove the pulley.
Clean
a l l
dirt and clippings off
the
Hydrogear and
surrounding area with solvent and compressed air
to keep the interior of the transaxle free of foreign
matter w'hen the Hydrogear
i s
separated from the
transaxle.
Place a drain pan
beneath the Hydrogear.