Snapper K50 User manual

TUFF TORQ MODEL K50/K55
HYDROSTATIC TRANSAXLE

TABLE OF CONTENTS
Section I - GENERAL INFORMATION.1.1-1.2
Section II - TROUBLESHOOTING.2.1-2.2
Section III - TRANSAXLE REMOVAL FROM TRACTOR...3.1-3.2
Section IV - TRANSAXLE DISASSEMBLY.4.1-4.10
Section V - TRANSAXLE ASSEMBLY..5.1-5.9
Section VI - TRANSAXLE INSTALLATION!.6.1-6.3
Section VII - PREPARING TRANSAXLE FOR OPERATION.7.1-7.2
NOTE
When making repairs that require replacement parts or
components, use only original SNAPPER replacement
parts to keep the equipment in top operating condition.
Refer to the appropriate parts manual for correct part
numbers and proper quantities required.
Copyright 1994 by SNAPPER. Any use of editorial or pictorial content, in any manner, without express, written consent is prohibited.

Section I
GENERAL INFORMATION

Section I - GENERAL INFORMATION
INTRODUCTION
HOW TO USE THIS MANUAL
This manual contains the Service and Maintenance infor¬
mation required to properly inspect, service and repair
a SNAPPER TUFF TORO Model K50/K55 Hydrostatic
Transaxle. The manual is divided into sections for quick,
easy reference. Carefully read all procedures described
for servicing a particular component BEFORE repairs are
started, to avoid needless disassembly.
WARNINGS & CAUTIONS
Details of standard workshop safety procedures are not
included in this manual. WARNING & CAUTIONS occur
where procedures, if improperly performed, could cause
personal injury and/or damage to the transaxle or its com¬
ponents. These WARNINGS & CAUTIONS do not cover
all conceivable ways hazardous consequences could be
created by improperly following the instructions or by the
incorrect use of service tools.
TOOL REQUIREMENTS
The normal complement of Standard and Metric tools
found in most repair shops are all that will normally be
needed to repair the SNAPPER TUFF TORQ Model
K50/K55 Hydrostatic Transaxle.

TROUBLESHOOTING
2.1

Section II - TROUBLESHOOTING
HYDROSTATIC TRANSAXLE
TRANSAXLE WILL NOT MOVE FORWARD OR IN REVERSE
Roll release lever is engaged.
Oil level low.
Input drive beit is slipping or broken.
Parking brake is set.
Stripped splines on input shaft.
Stripped keys on axles.
Broken axle or ring gear.
disengage iever
add oil
adjust/replace belt
release park brake
replace input shaft
repiace axie keys
repiace axle or ring gear
TRANSAXLE IS OVERHEATING
Oil level low.
Oil is of wrong type.
Cooiing fins on transaxie are clogged
Broken cooling fan blades.
Exceeding ioad rating for tractor. . .
Parking brake not fuiiy released . . .
check/add oil
drain, replace with specified oil
clean fins
repiace cooiing fan
reduce load
release park brake
LEAKING OIL
...from axle seals.replace axle seals and/or bushings
...from oil breather.overfilled, drain excess oil
FREEPLAY IN SHIFTER ARM
Shift blocks probably worn . .
check/replace shift blocks

TRANSAXLE REMOVAL FROM TRACTOR
3.1

Section III - TRANSAXLE REMOVAL FROM TRACTOR
TRANSAXLE REMOVAL
NOTE:
The following information covers removal of the
SNAPPER TUFF TORO Model K50/K55 Hydrostatic
Transaxle from SNAPPER LAWN TRACTORS.
Raise hood and disconnect spark plug wire.
Remove mower deck. See Operator's Manual.
Remove drain plug and seal washer from lowercase. See
Figure 3.1.
Allow oil to drain completely.
FIGURE 3.1
NOTE:
When reinstalling drain plug, use a new seal washer,
SNAPPER Part No. 9-1434, and torque drain plug to 20-
24 N»m (174-217 lb-in).
Elevate rear of tractor and support frame with jack stands.
Remove and discard rear wheel hubcaps.
Remove rear wheels.
Disconnect brake linkage from brake arm, located under
the right rear frame. See Figure 3.2.
Remove tractor drive belt. Refer to Operator's Manual
for instructions.
Remove hairpin and washer and disconnect transaxle
speed control linkage from front of transaxle. See Figure
3.3.
Remove mounting bolts from transaxle and tractor frame.
Lower transaxle and remove deck cable bracket.
Remove transaxle for service.
Remove all tractor parts which are attached to the tran¬
saxle. Refer to Section Vi, Figure 6.1 for parts break¬
down.
Transaxie is now ready for repair.
WASHER

Section IV
TRANSAXLE DISASSEMBLY

Section IV - TRANSAXLE DISASSEMBLY

Section IV - TRANSAXLE DISASSEMBLY
ITRANSAXLE HOUSING CASE SEPARATION
Remove seventeen capscrews to separate the transaxle
housing case. See Figure 4.4.
Separate the upper and lower halves of the housing case
by inserting a screwdriver between the halves at the five
(5) pry points and pry them apart. See Figure 4.5
Remove any remaining gasket material from both case
halves.
REMOVE SEVENTEEN (17)
12mm CAPSCREWS FROM
CASE
^ DO NOT REMOVE!
FACTORY-INSTALLED
PRESSURE FILL-PLUG.
Carefully inspect components and case halves for obvi¬
ous damage.
FIGURE 4.4
MAGNET REMOVAL & CLEANING
Pull magnet out of slot in lower case half. See Figure 4.6.
Clean magnet by blowing it with compressed air.
After cleaning, inspect the rubber seal around the mag¬
net for splits and brittleness. If damaged, replace with a
new magnet assembly.
Set the magnet aside for final assembly.
FIGURE 4.5
FIGURE 4.6

Section IV - TRANSAXLE DISASSEMBLY
Check the differential axle assembly components as fol¬
lows:
1. I nspect the ring gear for worn, broken or missing teeth.
See Figure 4.7.
2. C heck to make sure that the sides of the ring gear
have only floating contact with the walls of the case
half.
3. Check to see that the thrust plates are holding the
ring gear assembly in alignment.
4. Inspect the bevel gears for worn, broken or missing
teeth.
5. C heck to make sure that the axle shafts are smooth.
6. C heck to see that the differential bevel gears respond
instantly to movement of the axle shafts and bevel
gear splines.
FIGURE 4.7
7. C arefully inspect axle seals for leakage or damage.
NOTE:
If axle seals are not to be replaced, DO NOT remove dif¬
ferential axle assembly. Complete removal of the axles
require the installation of new seals.

Section IV - TRANSAXLE DISASSEMBLY
DIFFERENTIAL AXLE REMOVAL
NOTE:
Remove differential axie assembly BEFORE removing
pump and motor assembly. This sequence of removal
makes it easier to work on the pump - you do not have to
work around the ring gear.
Remove thrust washer from the "short axie" side. See
Figure 4.8.
Rotate the C-ring 180° in its siot so opening is facing down.
This wiil prevent the C-ring from dropping down into the
case. See Figure 4.9.
Hold the "short axle" bevel gear stationary as you siide
the axle outward to free the C-ring.
Remove C-ring from axle.
NOTE:
Do not remove axle at this point - it hoids the bevel gear
In place while the long axle side is being disassembled.
Repeat above procedures for "long axle" side.
Hold differential axle assembly by both bevel gears and
siide axles clear.
Remove gear assembly. See Figure 4.10.
Remove axles.
FIGURE 4.8
FIGURE 4.9
Remove axle seals.
Inspect condition of axle bushings, then measure the in¬
side diameter of each. The bushing ID should measure
NO LARGER than 19.2mm (0.76 inch) MAXIMUM! If the
bushings exceed specification, replace the upper case
housing - the bushings are not to be replaced.
Inspect all components of the ring gear and bevel gear
assemblies for signs of scoring, pitting, breakage or un¬
due wear. Replace components as required.
GEAR, SHAFT & AXLE SPECIFICATIONS
Bevel gear ID - 15.11mm (0.06 inch) MAXIMUM
Cross-shaft OD - 14.96mm (0.589 inch) MINIMUM
Axle OD (Long & Short) - 19mm (0.748 inch) MINIMUM
ASSEMBLY
FIGURE 4.10

Section IV - TRANSAXLE DISASSEMBLY
Install new axle shaft seals. Protect the new seals from
damage by wrapping tape around the axle splines and C-
ring groove before installing axle. See Figure 4.11.
NOTE:
Lube inside lip of axle shaft seal with GP grease or 30 wt
motor oil before installing.
DISASSEMBLY OF TRANSPORT
(FREE-WHEELING) ASSEMBLY
LOWER CASE HALF
The transport actuating bracket and pin are located in the
lower case half. Inspect the case on the outside for oil
leakage around the pin, then check the bracket and pin
for signs of wear. If everything is in good condition, set
the lower case aside until final assembly. See Figure 4.12.
If any sign of oil leakage is visible on the outside of the
lower case half, the transport assembly must be removed
from the case and the 0-ring on the pin replaced. See
Figure 4.13.
After removal, check the actuating bracket, pin and C-
ring for wear or damage. Replace components as re¬
quired.
FIGURE 4.11
CASE HALF
FIGURE 4.12
FIGURE 4.13

Section IV - TRANSAXLE DISASSEMBLY
UPPER CASE HALF
Remove filter. See Figure 4.14.
Remove push-pins, springs and push-pin guides from
valve body. Inspect all parts for wear or damage. Re¬
place as required.
Inspect transport valve bores and balls for wear or dam¬
age.
If any wear or damage is found, install the brake disc on
the output shaft and rotate the disc in both directions to
force the valve bodies from the housing. See Figure 4.15.
NOTE:
Hold a cloth over valve bores to catch valve body assem¬
blies as they are expelled.
If the valve assemblies are not expelled as the disc is
rotated back and forth, then remove the bleed port con¬
nector plug (Figure 4.14) and blow compressed air through
the bleed port to eject valve assemblies. Swap locations
of bleed port connector and pump plug to eject opposite
valve assembly with compressed air.
If the compressed air does not eject the valve assem¬
blies, carefully insert snap-ring pliers into the valve sleeves
and pull them out of the valve bores.
Check the bores for wear or damage. If required, replace
center block valve body.
Remove pump port plug and 0-ring from valve body.
DISC
FIGURE 4.15

Section IV - TRANSAXLE DISASSEMBLY
SHIFTER SHAFT DISASSEMBLY
Using a feeler gauge, measure the gap between the edge
of the swashplate slot and the shift blocks. The maxi¬
mum allowable gap is 0.15mm (0.0059 inch). If the gap
exceeds this dimension, replace both shift blocks. See
Figure 4.16.
Remove shifter shaft and shift blocks. See Figure 4.17.
Check end of shaft and mating surface in the case for
signs of wear. Replace components as required.
Remove existing 0-ring - a new one will be installed dur¬
ing reassembly.
PUMP, MOTOR & CENTER BLOCK
DISASSEMBLY
hA| CAUTION! |a1
Before proceeding with the disassembly of the
pump, motor & center block, BE AWARE that
they are assembled UNDER PRESSURE.
While disassembling, do not let these compo¬
nents FLY APART as they could be damaged
beyond use.
Remove the bleed port connector (if it was not previously
removed in the "Transport (Free-Wheeling) Assembly
Disassembly"). See Figure 4.18.
Remove and discard the two 0-rings.
O-RING-

Section IV - TRANSAXLE DISASSEMBLY
While keeping downward pressure on the assembly with
one hand, grasp the disc brake* on the end of the output
shaft with the other. Now, reposition the hand holding
down on the assembly to where it is holding the pump
and center block position. Press in towards the disc brake
end. See Figure 4.20.
Move motor, pump and center block assembly to a work¬
bench. Gradually release pressure on the components
and allow them to separate.
Leave these components for now; they will be inspected
and reassembled later.
REMOVAL OF PUMP SHAFT ASSEMBLY
Remove shaft seal. See Figure 4.21.
Remove snap ring.
Remove pump shaft assembly.
Inspect ball bearing for wear or damage.
If bearing is damaged, remove the snap rings and slide
the bearing off the shaft. See Figure 4.22.
Inspect shaft for damage. Replace as required.
PART NUMBERS
9-1438
SEAL, Input Shaft
(1)
9-1435
SNAP-RING
(1)
9-1458
SNAP-RING
(2)
9-1459
BEARING, Ball
(1)
9-1457
SHAFT, Pump Input
(1)
* DISC BRAKE SHOULD HAVE BEEN PREVIOUSLY
INSTALLED ON END OF OUTPUT SHAFT DURING
THE DISASSEMBLY OF THE TRANSPORT (FREE¬
WHEELING) ASSEMBLY.
PRESS "IN"
FROM BOTH
ENDS
FIGURE 4.21
4.9

Section IV - TRANSAXLE DISASSEMBLY
PUMP & SWASHPLATE DISASSEMBLY
Shown in Figure 4.23 are the components of the pump
and swashplate assembly. Familiarize yourself with all
components and their order of assembly before proceed¬
ing further.
NOTE:
The components in Figure 4.23 are shown in their normal
operating position (i.e., "up"). Disassembly of these com¬
ponents will take place with the upper case housing up¬
side-down on the workbench.
Separate, clean and inspect all components. Measure
thrust bushings for minimum thickness -1.3mm (0.05
inch). Inspect surfaces of all components individually -
they should be free of rust, pitting, scoring, etc. to be
serviceable. Replace parts as required.
REMOVED IN
PREVIOUS
0^^ I- DISASSEMBLY
OF PUMP
INPUT SHAFT
^ -THRUST BUSHING (2)
PUMP SWASHPLATE
PUMP & MOTOR
CENTER BLOCK
THRUST PLATE-TOP
MOTOR
CYLINDER
BLOCK motor
SWASHPLATE
BEARING
THRUST PLATE - BTM
PUMP INPUT
SHAFT (REMOVED
IN PREVIOUS
DISASSEMBLY)
PUMP CYLINDER
BLOCK
PUMP PLATE
FIXED SWASHPLATE
HOUSING
XT
PUMP PISTON WASHER
CYLINDER BLOCK PISTON
MOTOR OUTPUT SHAFT
BALL BEARING —'
BALL BEARING
/
4.10

TRANSAXLE ASSEMBLY

Section V - TRANSAXLE ASSEMBLY
ASSEMBLY & INSTALLATION
PUMP SHAFT ASSEMBLY
Coat all components with 10W-30 Class FSCD Motor Oil
before assembly.
Assemble components of pump shaft assembly and in¬
stall it into the upper case. See Figure 5.1.
Secure the pump shaft into the upper case with the snap
ring.
Wrap tape around splines on end of shaft to protect seal.
Coat lip surfaces of seal with GP grease or motor oil be¬
fore installation. Refer to Figure 5.1.
SWASHPLATE & SHIFTER SHAFT ASSEMBLY
Install thrust plates. See Figure 5.2.
Install a new 0-ring on the shifter shaft.
Apply GP grease to iriside of shaft blocks to help them
adhere to the shifter ball.
Fit the swashplate, shift blocks and shifter shaft together.
While holding these components together, fit them into
the upper case half. See Figure 5.3.
5.2