2-S35
ZD321, ZD326, ZD331, WSM
TRANSAXLE
6. SERVICING
[1] HYDROSTATIC TRANSMISSION
Center Section
1. Check the surface (1) of center section for scratches or wear. If
deep scratch or excessive wear is found, replace the hydrostatic
transmission assembly.
W1038177
Check and High Pressure Relief Valve
1. Check the check and high pressure relief valve assembly (3) for
scratches and damage.
2. Check the spring (2) for breakage and wear.
3. If anything unusual, replace the ball and spring.
W1038284
Cylinder Block Assembly
1. Check the cylinder blocks (1) and pistons (2) for scratches and
wear.
2. If scratch or worn, replace the cylinder block assembly.
3. Check that the piston (2) and spring (3) are in each cylinder bore.
4. Check the pistons for their free movement in the cylinder block
bores.
5. If the piston or the cylinder block is scored, replace the cylinder
block assembly.
6. Check the polished face (4) or cylinder block for scoring.
7. If scored, replace the cylinder block assembly.
• Do not interchange pistons between pump and motor
cylinder block. Pistons and cylinder blocks are matched.
W1038472
Thrust Washer, Thrust Ball Bearing and Thrust Plate
1. Check the thrust ball bearing (3) for scratches and excessive
wear.
2. If worn, replace.
3. Check the thrust plate (4) for scratches and excessive wear.
4. If worn or scored, replace.
W1038722
(1) Surface
(1) Plug
(2) Spring
(3) Check and High Pressure Relief
Valve Assembly
(1) Cylinder Block
(2) Piston
(3) Spring
(4) Polished Face
(1) Swashplate
(2) Thrust Washer
(3) Thrust Ball Bearing
(4) Thrust Plate