165-5777 final drive for Caterpillar 315C midi excavator

315C Final Drive for CAT Excavator spare parts 165‑5777 1655777 210‑3529 2103529 Axial Piston Motor

Product Overview

The CAT 315C is the C‑series predecessor to the 315D — a 15‑ton excavator that spent years on tight urban jobs, basement digs and utility trenches before the D‑series took over. Under each track frame sits the axial piston motor and planetary reducer, covered by references 165‑5777, 1655777, 210‑3529 and 2103529, that takes pump flow and turns it into the slow, steady pull moving the machine between pipe runs.

On an older C‑series CAT, the drive wears down in quiet stages that are easy to miss. The operator notices the two tracks no longer quite match on a flat driveway, that one track warms after a shorter trundle than it should, and that a new sound comes through the floor that was not there last month. Most crews keep digging until a track hesitates on a curb — but by then the piston block and valve plate have already been lapping swarf into the oil. This aftermarket unit reproduces the original motor‑and‑reducer pairing as one sealed, bench‑run assembly, so the worn drive lifts out whole and the new one bolts straight in.

Core Advantages

1. Keeps an older C‑series workhorse earning
Original drives for the 315C grow harder to source as the fleet ages. This aftermarket unit gives owners a path to keep a still‑useful machine on the job rather than writing it off over a dead track.

2. Even track pull on tight urban sites
A lapped piston block and valve plate hold pressure internally, so neither track lags. The machine tracks straight across a driveway without the operator fighting a sideways tug.

3. Hardened gears for curb climbs and trench edges
Case‑hardened planetary teeth absorb the shock of pulling up over curbs and spoil piles, and controlled backlash keeps the drive quiet on residential streets.

4. Sealed against city dust and washdown water
Urban yards mean dust, mud and pressure washing. Fresh shaft and housing seals keep that grit out of the lube — the detail that decides whether the drive lasts or fails early.

5. A direct, drop‑in fit
Flange, studs and ports reproduce the original, so removal and refitting follow the old CAT manual. No adapters, no fabrication, no guessing.

Manufacturing & Quality Control

Components are machined to the original drawing, heat‑treated where wear bites, and assembled in a clean area. Each finished drive runs on a hydraulic stand while torque, leakage and noise are checked; units outside tolerance are reworked before packing. The internals are fogged with preservation oil, ports are plugged, and the unit is crated on dunnage for freight.

Frequently Asked Questions

Q1: Which of the four references suits my 315C?
A: Read the tag on your existing drive against the four numbers and send the machine serial number. The references cover build variants across the C series, so we confirm the correct unit before dispatch.

Q2: Is this interchangeable with the later 315D drive?
A: The 315C and 315D use related but not always identical drives. Mounting and output spline can differ. Send the serial number and we will tell you honestly whether it crosses over.

Q3: What symptoms mean the drive is tired?
A: Mismatched track speeds, pulling to one side, a warm or noisy track motor, and hesitation under load. Catch it before swarf spreads through the travel circuit.

Q4: Do you sell just the gearbox if the motor is fine?
A: The listing is the complete assembly. If you have diagnosed only one side, ask about cartridges and internal kits — we can usually supply them separately.

Q5: What is the warranty position?
A: Materials and build defects are covered. Damage from dirty oil, debris in the motor, track obstruction, overload or incorrect fitting is excluded. Photograph any arrival damage before uncrating.