Husqvarna Tuff Torq K61 User manual

i
T a b l e o f C o n t e n t s
Ordering Replacement Parts Online .................................ii
Icons Used in this Manual .....................................................iv
Recommended Tools and Equipment .............................iv
Serial Number Locations .......................................................iv
Specifications: ...........................................................................iv
Disassembly of Transaxle ..........................1
Axel Shafts and Differential Gear Assemblies ...............7
Axle Seal Removal ...................................................................8
Axle Shaft and Bushing Tolerances ...................................7
Brake Assembly Removal ......................................................1
Bypass Valve Removal ...........................................................4
“C” Arm Removal .....................................................................3
Center Case & Motor Shaft Ass’y Removal ......................9
Center Case Removal .............................................................10
Cylinder Block (Motor) Assembly Removal ....................10
Cylinder Block Assembly (Pump) Removal .....................12
Differential Gear Assembly Removal ................................8
Differential Gear Assembly Removal ................................5
Differential Pinion Shaft and Gear Tolerance ................8
Drain Oil ......................................................................................1
Filter Removal ...........................................................................3
Final Pinion Shaft and Bushing Tolerances ....................5
Final Pinon Assembly .............................................................4
Final Pinon Assembly Removal ...........................................4
Fulcrum Removal .....................................................................14
Hydraulic Flow Diagram ........................................................17
Hydrostatic Pump Removal .................................................9
Levers (Shafts) and Linkage Removal ...............................16
Lower Case Removal ..............................................................3
Magnet Removal .....................................................................9
Motor Housing Removal .......................................................10
Motor Shaft Removal .............................................................11
Pump Shaft Removal ..............................................................15
Shock Absorber and Control Arms Removal .................2
Swash Plate Removal ..............................................................13
Assembly of Transaxle ...............................18
Adjusting Neutral ....................................................................36
Axle Shafts and Differential Gear Assembly ..................30
Before Starting Assembly .....................................................18
Bleeding Air from Hydrostate Oil Circuit .........................36
Brake Assembly ........................................................................35
Bypass Shaft Assembly ..........................................................18
Center Case Assembly ...........................................................27
Cylinder Block (Pump) Assembly .......................................24
Differential Gear Assembly ..................................................30
Lower and Upper Case Assembly ......................................33
Motor Shaft/Center Case Assembly ..................................28
Motor Shaft Assembly ...........................................................25
Oil Change Frequency ...........................................................37
Oil Requirement .......................................................................37
Final Pinon Shaft Assembly .................................................32
Post Assembly Procedures ...................................................36
Pump Shaft Assembly ............................................................22
Swash Plate Assembly ............................................................24
Troubleshooting and Diagnosis Guides ....38

iv
Icons Used in this Manual
This symbol identifies the presents of IMPOR-
TANT, if not critical, information.
This symbol is intended to alert you of important
technical information and/or maintenance procedures
which will better assist you in the disassembly and re-
assembly of the Transaxle.
This symbol offers suggestions which will bet-
ter assist you in the disassembly and reassembly of
Transaxle.
This symbol indicates when an application of
grease or oil is to be applied to the part prior to its as-
sembly.
Recommended Tools and Equipment
1. Transaxle Service Stand (Part Number 1111)
2. Black Electrical Tape
3. Needle Nose Pliers
4. O.D. Retaining Ring Pliers
5. I.D. Retaining Ring Pliers
6. Neoprene Hammer
7. Ball Peen Hammer
8. Telescoping Magnetic Pickup
9. Flathead Screw Driver
10. Roll Pin Punch
11. Feeler Gauge
12. Calipers
13. Putty Knife
14. Wrench (size):
8 millimeter
12 millimeter
14 millimeter
17 millimeter
15. Sealant
16. Grease
17. Filter
18. Seal Kit (s)
19. Oil (10W 30 Class CC or CD)
Specifications:
Transaxle Torque output .......................217 Ft. lbs.
Maximum Input Speed ..........................3000 RPM
Input Shaft Size .........................................14.85 mm (0.58 in.)
Reduction Ratio ........................................18.79 : 1 or 26.97 : 1
Axle Shaft Size ...........................................25.4 mm (1.0 in.)
Maximum Static Weight on Axle ........265 kg (584 lbs.)
Weight (Dry) ...............................................17.5 kg (38 lbs.)
Brake .............................................................Dry Band
Brake Capacity ...........................................390 N-m (288 ft. lbs.)
.........................................................................at 245 N m (55 lbs.)
.........................................................................Brake Force
Differential ..................................................Automotive Type
.........................................................................Bevel Gears
Gears .............................................................Heat-Treated
Automatic Neutral Return .....................Standard
Housing ........................................................Aluminum Die Castings
Tow Value ....................................................Std. (Brake Release)
Oil ...................................................................10W 30 Class CC or CD
Oil Capacity ................................................3.3 liters (3.5 qts.)
Serial Number Locations
Service Stand (Part Number 1111)
This manual is applicable for repair of all (9) K61 models
built and distributed by Tuff Torq.
K61C, K61D, K61E, K61F, K61I, K61J, K61M, K61N, and
K61O

1
Tuff Torq K61 Hydrostatic Transaxle
Drain Oil
Before beginning tear-down clean work area
thoroughly and cover workbench with clean paper.
This is extremely important as just one grain of sand
can cause damage to the Hydrostatic Rotating Group
in the Transaxle.
1. Remove the Oil Drain Plug (12 mm wrench) from the
Lower Case of Transaxle and drain oil. (Fig. 1)
2. Remove the Connector (14 mm wrench) from the Center
Case, through the Lower Case and drain the oil from the
Hydrostatic Rotating Groups. (Fig. 1)
Fig. 1, Oil Drain Plug and Pressure Fill Plug removal
Always install a new Seal Washer on the Drain
Plug and new O-rings on Pressure Fill Plug when reas-
sembling.
Brake Assembly Removal
1. Remove the Cotter Pin and Washer from the Brake Rod
Assembly. (Fig. 2)
2. Remove the Brake Rod Assembly from Brake Arm B (see
Fig. 3) by pivoting 90 degrees and sliding downward.
(Fig. 2)
3. Loosen and remove the (3) 8 mm bolts/washers (12mm
wrench) and detach the Brake Assembly. (Fig. 2)
4. Remove Snap Ring (Snap Ring Pliers) and the Brake
Drum from Brake Shaft. (Fig. 2)
Fig. 2, Brake Assembly Removal
Inspect all brake components for wear or dam-
age. Replace as necessary.
Brake drum and brake band are to be free from
oil and dust.
Disassembly of Transaxle

2
Fig. 3, Levers and Arms Removal
Shock Absorber and Control Arms Removal
(On K61 Models where applicable)
1. Remove the Shock Absorber. (Fig. 3)
2. Remove the Roll Pin and the H-Control Arm from the
Control Shaft. (Fig. 4)
3. Remove the Roll Pin and the Brake Arm from the Brake
Shaft. (Fig. 4)
4. Remove the Roll Pin and Brake Arm “B” from Brake Arm
“A”. (Fig. 4)
5. Remove the Roll Pin and the (Tow) Release Valve Arm
from the Bypass Shaft. (Fig. 4)
Fig. 4, Arms and Roll Pins

3
Tuff Torq K61 Hydrostatic Transaxle
Lower Case Removal
1. Place the Transaxle on a Service Stand in the serviceable
position (Lower Case up), to keep it steady during tear-
down. (See “Recommended Tools and Equipment”).
Service Stand (Part Number 1111) can be or-
dered online or through your local Tuff Torq distribitor.
See page iv, “Recommended Tools and Equipment.”
2. Remove the (14) bolts (8 mm) securing the Transaxle’s
Upper and Lower Cases. Lift the Lower Case away from
the Upper Case, exposing the internal parts.
(Fig. 5)
Fig. 5, Upper and Lower Housing Removal
If separation does not occur easily, a screw-
driver can be inserted at any of the (4) pry points (indi-
cated by the black arrows) (Fig. 6)
Fig. 6, Pry Points
Care should be taken not to damage the Hous-
ing Sealing lips while prying apart. Remove any old
sealant residue from both case halves.
Filter Removal
1. Remove the Filter from the Center Case and discard.
(Fig. 7)
Fig. 7, Filter Removal
Install a new filter any time case halves are
separated.
“C” Arm Removal
1. Disconnect “C” Arm from the Bypass Shaft by applying
slight sideward pressure to the spring loaded Push Pins.
This will keep them from springing out. With the Push
Pins secure, lift the “C” Arm off the Push Valve Bypass
Shaft. (Fig. 8, 9)
Fig. 8, “C” Arm Removal

4
1. Remove (2) Push Pins, Springs, and Bypass Valve from
the Center Case. (Fig. 9)
Fig. 9, Push Pin and Bypass Valve Removal
Final Pinon Assembly
1. Remove the Final Pinion Assembly from the Upper Case
from its seated position. Separate the assembly, Bear-
ing, Bushing, Washer, Final Pinon Shaft, and Reduction.
(Fig. 10, 11)
2. Inspect the Final Pinion Shaft and the Reduction Gear
for scoring, pitting, discoloration and chipped or broken
teeth. (Fig. 11)
Fig. 11, Final Pinion Assembly
Carefully inspect all parts for wear or damage.
Replace as necessary.
Fig 10, Final Pinon Assembly Removal
Bypass Valve Removal
Final Pinion Assembly Removal

5
Tuff Torq K61 Hydrostatic Transaxle
2. Measure the I. D. (Y) of the “loose” Bushing. (Fig. 12)
3. If the clearance (Y-X) is > 0.50 mm (.019 in), replace the
Final Pinion Shaft and/or Bushing.
◆ Example of an Acceptable Tolerance:
Pinion Shaft O. D. (X) = 14.79 mm
Bushing I. D. (Y) = 15.27 mm
Y (15.27 mm) - X (14.79 mm) = 0.48 mm of
clearance.
◆ Example of an Unacceptable Tolerance:
Pinion Shaft O. D. (X) = 14.75 mm
Bushing I. D. (Y) = 15.29 mm
Y (15.29 mm) - X (14.75 mm) = 0.54 mm of
clearance. This is > the wear limit of 0.50
mm, replacement is necessary.
Fig 13, Differential Gear Assembly and Axle Removal
Final Pinion Shaft and Bushing Tolerances
1. Using calipers (digital recommended) measure the O. D.
(X) of the Final Pinion Shaft. (Fig. 12)
Fig. 12, Final Pinion Shaft and “Loose” Bushing Clearance
Differential Gear Assembly Removal

6
Rotating the Axle until open end of C-Ring is
facing downward will prevent C-Ring from dropping into
Upper Case.
5. Carefully back out and remove the Left and Right Axle
Shafts. (Fig. 14, 16)
6. Remove (2) “loose” Bushings from the Upper Case.
(Fig. 16)
Inspect the Axle Shafts and Bushings for scor-
ing, pitting, discoloration, damaged ring grooves, and
chipped or broken splines. Replace as necessary.
Fig 14, Differential Gear Assembly and Axle Removal
Differential Gear Assembly Removal (continued)
1. Remove Thrust Washer from either the Left or Right Axle.
(Fig. 14, 16)
2. After removing the Thrust Washer, rotate the Axle until
the open end of C-Ring is facing downward. Holding the
Differential Side Gear stationary, slightly slide the Axle
outward exposing the C-Ring. Using a Telescoping Mag-
net, remove C-Ring. (Fig. 14, 16)
3. Repeat steps 1 and 2 for opposing shaft.
4. With the Thrust Washers and C-Rings removed, hold
the Gear Assembly in place. Carefully back out both
Axle Shafts until the shafts splines clear the Side Gears.
Remove the Gear Assembly and inspect components for
wear or damage. (Fig. 15)

7
Tuff Torq K61 Hydrostatic Transaxle
Axle Shaft and Bushing Tolerances
1. Using calipers (digital recommended) measure the O. D.
(X) of the Axle Shaft. (Fig. 15)
Fig. 15, Axle Shaft and “Loose” Bushing Clearance
2. Measure the I. D. (Y) of the “Loose” Bushing. (Fig. 15)
3. If the clearance (Y-X) is > 0.35 mm (0.014 in), replace the
Axle Shaft and/or “loose” Bushing.
◆ Example of an Unacceptable Tolerance:
Axle Shaft O. D. (X) = 18.89 mm
Bushing I. D. (Y) = 19.25 mm
Y (19.25 mm) - X (18.89 mm) = 0.36 mm of
clearance. This is > the wear limit of 0.35 mm,
replacement is necessary.
Fig. 16, Differential Gear and Axles
Axel Shafts and Differential Gear Assemblies

8
Differential Gear Assembly Removal
1. Remove the Differential Side Gears, Thrust Washers, Dif-
ferential Pinion Gears, and the Differential Pinion Shaft
from the Final Gear. (Fig. 17)
2. Inspect the Side and Pinion Gears and Pinion Shaft for
scoring, pitting, discoloration and chipped or broken
teeth.
Fig. 17, Differential Gear Assembly
Axle Seal Removal
1. After the Differential Gear Assembly and Axles have
been removed, take out the (2) Axle Seals at each end of
the Upper Case. (Fig. 19)
Fig. 19, Axle Seal Removal
Extreme caution should be taken when remov-
ing Seals from the Upper Case. Immediately behind
each Axle Seal is a press-fit bushing. If damaged, the
Upper Case must be replaced, bushings can not be
replaced separately.
Seals should be replaced every time the Axles
are removed.
2. Measure the I. D. (Y) of the Pinion Gears. (Fig. 18)
3. If the clearance (Y-X) is > 0.50 mm (0.019 in), replace the
Pinion Shaft and/or Pinion Gears.
◆ Example of an Unacceptable Tolerance:
Pinion Shaft O. D. (X) = 14.75 mm
Pinion Gear I. D. (Y) = 15.30 mm
Y (15.30 mm) - X (14.75 mm) = 0.55 mm of
clearance. This is > the wear limit of 0.50 mm,
replacement is necessary.
Differential Pinion Shaft and Gears Tolerance
1. Using calipers (digital recommended) measure the O. D.
(X) of the Pinion Shaft. (Fig. 18)
Fig. 18, Differential Pinion Shaft and Pinion Gears Clearance

9
Tuff Torq K61 Hydrostatic Transaxle
Center Case & Motor Shaft Ass’y Removal
2. After removing the remaining two bolts holding the
Center Case to the Upper Case, place one hand over
the Motor Housing and the other hand over the Cen-
ter Case. While compressing both portions together
slightly, lift the entire assembly from the Upper Case.
(Fig. 22)
Fig. 22, Center Case and Motor Shaft Assemblies
Magnet Removal
1. Loosen (3) Bolts (10 mm) — removing one, on the Cen-
ter Case; remove the Magnet. Clean the Magnet thor-
oughly before reassembling. (Fig. 21)
Fig. 21, Magnet Removal
Fig. 20, Center Case and Motor Shaft Assemblies
Hydrostatic Pump Removal
Slide the Brake Drum onto the
Motor Shaft to provide a means of grip-
ing and lifting the Center Case and Mo-
tor Shaft Assemblies from the Upper
Case.

10
Cylinder Block (Motor) Assembly Removal
4. Remove the Cylinder Block Assembly from the Motor
Shaft. (Fig. 25)
5. Inspect each component of the Cylinder Block Assembly
for burrs, scoring, pitting, discoloration, distortion, and
wear.
Fig. 25, Cylinder Block Assembly
If any of the components of Cylinder Block As-
sembly are damaged, they must be replaced with a
complete Cylinder Block Assembly. Individual compo-
nents are not serviced separately.
Be careful that the Pistons do not fall out of
Cylinder Block. Do not set Cylinder Block down with
mating surface contacting table top, as this can cause
damage to the machined surfaces.
Fig. 26, Finger placement during removal
To avoid the pistons from dropping out during
removal of the assembly, position fingers around the
Cylinder in order to apply pressure on each of the five
pistons. (Fig. 26)
Hydrostatic Pump Removal (continued)
Center Case Removal
3. While still maintaining pressure on the Cylinder Block
Assembly and the Motor Housing, carefully separate the
Center Case from the Motor Shaft Assembly. (Fig. 23)
Fig. 23, Center Case and Motor Shaft Assembly
During separation, be careful not to damage
contact surfaces of Center Case and Cylinder Blocks.
(Fig. 24)
Fig. 24, Center Case and Cylinder Block, Machined Surfaces
Inspect the machined surfaces of the Center
Case. If excessive scratches are detected, replace the
Center Case and both Cylinder Block Assemblies, si-
multaneously.

11
Tuff Torq K61 Hydrostatic Transaxle
Motor Shaft Removal
9. Withdraw the Motor Shaft from the Motor Housing. If
the Shaft doesn’t back out freely, check to see if Snap
Ring was removed, see step 6. (Fig. 29)
10. Remove the Snap Ring and Washer. Inspect the Washer
for wear or damage and replace if necessary.
(Fig. 29)
Fig. 29, Motor Shaft Removal
There is no need to remove the press-fit Bear-
ing on the Motor Shaft, unless it is damaged or worn.
Motor Housing Removal
6. Remove the Spring and Snap Ring. Next, remove the
Thrust Bearing Set seated in the Motor Housing. (Fig. 27)
7. Inspect the press-fit Bushing in the Motor Housing for
burrs, scoring, pitting, discoloration, and wear. If dam-
aged, replace the Motor Housing. press-fit Bushings are
not serviced separately.
8. Remove the Snap Ring and Seal. Discard the Seal and
replace it with a new Seal during reassembly. (Fig. 27)
Fig. 27, Motor Shaft and Housing
Fig. 28, Motor Shaft Assembly
Hydrostatic Pump Removal (continued)

12
Cylinder Block Assembly (Pump) Removal
11. Remove the Cylinder Block Assembly from the Pump
Shaft. (Fig. 30)
Fig. 30, Cylinder Block Removal from Pump Shaft
12. Inspect each component of the Pump Cylinder Block As-
sembly for burrs, scoring, pitting, discoloration, distor-
tion, and wear. (Fig. 31)
Fig. 31, Cylinder Block Removal
If any of the components of the Cylinder Block
Assembly are damaged, the complete assembly must
be replaced. Individual components are not serviced
separately.
Take care to insure that the Pistons do not fall
out of Cylinder Block. Do not set Cylinder Block down
with mating surface contacting table top, as this also
could cause damage.
To avoid the pistons from dropping out during
removal of the assembly, position fingers around the
Cylinder in order to apply even pressure to all five pis-
tons. (Fig. 32)
Fig. 32, Finger Placement During Removal
During separation, be careful not to damage
contact surfaces of Center Case and Cylinder Blocks.
(Fig. 33)
Fig. 33, Center Case Machined Surfaces
Inspect the machined surfaces of the Center
Case. If excessive scratches are detected, replace the
Center Case and both Cylinder Block Assemblies, si-
multaneously. (Fig. 33)
Hydrostatic Pump Removal (continued)

13
Tuff Torq K61 Hydrostatic Transaxle
6. Remove the (2) Thrust Metals (bearing pads) from the
Upper Case. (Fig. 36)
Fig. 36, Thrust Metal Bearing Removal
Inspect Thrust Bearing components for pitting,
scoring, discoloration, missing rollers, and roller retain-
er breakage.
Fig. 37, Cylinder Block Assembly & Swash Plate
Swash Plate Removal
1. Before removing the Swash Plate Assembly measure the
clearance (using Feeler gauge) between edge of Swash
Plate’s Slot and the Shift Blocks. If the clearance (gap) is
> 0.15 mm (0.005 in), replace both Shift Blocks and the
Swash Plate Assembly, simultaneously. (Fig. 34)
Fig. 34, Shift Blocks Clearance Tolerance
2. Remove the Spring and the Snap Ring. (Fig. 35)
Fig. 35, Swash Plate Removal
3. Remove the Thrust Bearing seated in the Swash Plate.
(Fig. 36)
4. Remove the Swash Plate. (Fig. 36)
5. Inspect the press-fit Bushing in the Swash Plate for
burrs, scoring, pitting, discoloration, and wear. If dam-
age, replace the Swash Plate. The press-fit Bushings are
not serviceable separately.
Do not attempt to remove the press-fit Bushing
in the Swash Plate. If damaged, replace Swash Plate
Assembly (press-fit Bushing is included in the assem-
bly).

14
Fulcrum Removal
1. Remove the Nut (17mm) and Washer from the Fulcrum
(Neutral Adjust Eccentric). (Fig. 40)
Fig. 40, Fulcrum Removal, from top of Upper Case
2. Return the Upper Case to its service position (Flange
side up) and remove the Fulcrum. (Fig. 41)
3. Inspect the Fulcrum Cam for wear or damage, replace if
required.
4. Remove and discard (2) O-rings and replace with a fresh
pair. (Fig. 41)
Fig. 41, Fulcrum
Swash Plate Removal (continued)
Fig. 38, Swash Plate’s Machined Ramps
Inspect the Swash Plate’s machined ramp sur-
faces and Press-Fit Bushings for scoring, pitting, dis-
coloration, and wear. If the Swash Plate and/or Bush-
ings are damaged, they must be replaced as a group.
7. Using calipers (digital recommended) measure the
thickness of both Thrust Metals for wear. If the clear-
ance is < 1.30 mm (0.051 in), replace Thrust Metals as a
set. (Fig. 39)
Fig. 39, Thrust Metals Tolerance
Always replace the Thrust Metals worn beyond
wear limits as a group.

15
Tuff Torq K61 Hydrostatic Transaxle
Fig. 43, Pump Shaft
Do not attempt to remove the press-fit Bearing
on the Pump Shaft unless it is damage or worn. Re-
moval could result in damage to the Bearing.
Pump Shaft Removal
1. Remove the Seal and discard. Replace with new a Seal
during reassembly. (Fig. 42)
2. Remove the large internal Snap Ring and lift the Pump
Shaft from the Upper Case. (Fig. 43)
Inspect the Shaft and its components for scor-
ing, pitting, discoloration, and other wear. Replace if
damage or worn. Inspect the Pump Shaft splines for
chipped or broken teeth.
Fig. 42, Pump Shaft Seal Removal

16
Fig. 45, Bypass Shaft and Spring
Inspect all Levers and Linkage for scoring, pit-
ting, discoloration, or any other visual damaged. Re-
place as necessary.
Levers (Shafts) and Linkage Removal
1. Remove the Control Shaft Assembly.
2. Remove the Fulcrum. Refer to page 14 for more details.
3. Disconnect Snap Pin from the Brake Rod (see arrow ➊)
and remove Washer. (Fig. 44)
4. Disengage the Brake Rod from Brake Arm “A” (see arrow
➋) and remove the Brake Rod. (Fig. 44)
5. Remove Brake Arm “A.” (Fig. 44)
6. Disengage the Brake Return Spring from the Brake Shaft
and the Upper Case, remove the Spring after steps 8 and
9.
7. Disengage the Bypass Rod from the slot on the Brake
Shaft. Remove the Bypass Rod. (Fig. 45)
8. Remove the Brake Shaft. (Fig. 45)
9. Remove the Bypass Shaft and Spring. (Fig. 45)
Remove and discard O-rings on Shafts. Replace
with new O-rings before reassembly. Refer to the As-
sembly section for further information.
Fig. 44, Levers and Linkage Removal
(If Applicable)
The Torsion Spring, shown here disassembled for clarity
only, should be handled (removing and installing) as a sin-
gle item. For assembly refer to “ Control Shaft & Fulcrum
Assembly,” on page 21.

17
Tuff Torq K61 Hydrostatic Transaxle
Hydraulic Flow Diagram