Gearbox, motor and complete travel unit are three purchases
The hydraulic motor converts oil flow into rotation. The planetary gearbox reduces speed and raises torque at the sprocket. A complete travel unit combines both.
| Purchase | Included assembly | Existing component retained |
|---|---|---|
| Gearbox only | Planetary gears, bearings, housing and output | Hydraulic motor |
| Travel motor only | Hydraulic motor and its control/brake arrangement | Planetary gearbox |
| Complete drive | Selected motor plus planetary gearbox | Complete old drive removed |
507-6559 is a left-side gearbox without the motor
The Cat 507-6559 entry is a left-hand final drive without a hydraulic motor. Its purchase scope therefore differs from a complete motor-and-gearbox offer. The 320D and 320D2 repair examples retain the machine prefix alongside this gearbox identity.
| Field | Value |
|---|---|
| Part number | 507-6559 |
| Position | Left-hand final drive |
| Assembly | Final reduction gearbox |
| Hydraulic motor | Separate purchase |
| Machine examples | 320D / 320D2 / 323D variants by installed drive |
Compact and medium excavator drives have separate assembly numbers
A Bobcat 7009157 is a travel-motor gearbox entry for E32/E35-family compact excavators. Komatsu PC200-7 uses 20Y-27-00300 final-drive and 708-8F-00170 travel-motor entries; PC200-8 uses 20Y-27-00500 and 708-8F-00250 entries.
| Machine | Final-drive / gearbox | Motor identity |
|---|---|---|
| Cat 320D-family LH | 507-6559 | Separate installed motor |
| Bobcat E32 / E35-family | 7009157 travel-motor gearbox | Separate motor entry |
| Komatsu PC200-7 | 20Y-27-00300 | 708-8F-00170 |
| Komatsu PC200-8 | 20Y-27-00500 | 708-8F-00250 |
Use the two mounting faces and the port layout
Record the machine-frame fixing circle and sprocket fixing circle separately. Each needs its hole count, hole diameter and bolt-circle dimension. On a complete drive, the A/B work ports, drain, two-speed pilot and brake arrangement also describe the installation.
| Location | Purchase detail |
|---|---|
| Frame mounting | Hole count, bolt circle and mounting pilot |
| Sprocket face | Hole count, bolt circle, offset and output form |
| Hydraulic motor | A/B ports, drain, speed-control and brake connections |
| Planetary gearbox | Part number, reduction ratio and output arrangement |
Build a gearbox repair or a complete-drive order
For a gearbox repair, list the gearbox, joint seals and gear oil as separate items while retaining the old motor identity. For a motor repair, specify the motor and its connecting seals. New replacement, original and rebuilt assemblies are separate offers with their own supplied condition.
Buying questions
Does 507-6559 include a hydraulic motor?
No. It identifies the left-hand final drive without the motor. A complete travel unit uses a separate motor-and-gearbox purchase line.
Is a travel motor the same as a final-drive gearbox?
The motor converts hydraulic power into rotation; the planetary gearbox changes speed and torque. A complete unit contains the selected combination.
What measurements matter on a first purchase?
The frame and sprocket mounting circles, pilots and hole counts define the mechanical fit. The motor port layout and two-speed control define its hydraulic connection.
Can a rebuilt offer be compared with a new offer?
Yes. Keep the condition, assembly scope, supplied controls and test record beside each price so a rebuilt original unit and a new replacement remain distinct offers.