Description

Fiat Hitachi D350 Repair Manual

You have a D350 on the lift and you are staring at a hydraulic leak or a transmission that won’t grab. The aftermarket CD you bought last year gave you a torque spec that stripped the converter housing. I’ve seen it happen. That’s why you need the real thing: the Fiat Hitachi D350 Repair Manual. This is the same 337-page binder the factory sent to their authorized service network. No generic data. No translation errors. Fiat Hitachi engineering, printed in Italian, with every spec you need to keep that track loader moving.

Engine Data for the QSM 11 Series

The manual opens with the QSM 11-C engine. General characteristics, mounting frame specs, and the fan-driven aftercooler control system. Page 1 shows the warning symbol – do not skip that page. Page 2 spells out the safety rules that keep you from getting crushed. The torque table for the cylinder head is in the general section. Use those values. Aftermarket manuals often list 90 ft-lbs for the QSM 11; the factory calls for 105 ft-lbs with a specific sequence. You torque it wrong, you get head gasket failure inside 50 hours.

Transmission Hydraulic Circuit: Diagnosis and Pressure Tests

The converter and transmission section is the thickest part of this manual. It covers the hydraulic flow from the pump through the torque converter to the speed clutches. You get the flow diagram (fig. 2-1) and the test procedure for converter stall pressures. The manual walks you through the distributor valve bench test, the pump flow rate check, and the shift solenoid troubleshooting. Do not start pulling the transmission without the pressure specs. The manual gives you the exact values for the clutch pack engagement pressures at full throttle. I’ve seen guys waste two days chasing a slipping clutch because they used a generic chart. Pull the factory data from this book.

For the basics of how a manual transmission works, see Manual Transmission on Wikipedia. The D350 uses a power-shift design, but the underlying principles apply.

Side Reducer Disassembly and Seal Installation

Side reducers on the D350 take a beating. The manual dedicates a full chapter to the lateral reduction unit. It covers removing the final drive, disassembling the planetary gears, and installing the long-life rotating front seals. The seal installation procedure includes a specific tool number and a note about pre-soaking the seal in oil. Miss that step and the seal leaks within a month. The manual also lists the bearing fit tolerances for the shafts – you need those numbers if you are replacing bearings. The parts list with exploded views helps you identify every shim and spacer. No guesswork.

Brake and Steering Differential Circuit Checks

Brake and steering share a hydraulic circuit in the D350. The manual gives you the full hydraulic schematic for both systems. You get the calibration procedure for the steering levers and the pressure adjustment on the brake feed valve block. The diagnostics section includes a display readout interpretation – if your machine has the optional electronic display, this tells you what each code means. The pedal brake valve disassembly steps are spelled out with torque values for the retaining bolts. Do not skip the pressure test. Page 2 reminds you: never work on the machine with the engine running. That rule saves lives.

Another resource on transmission fundamentals is Manual Transmission – a good refresher for any heavy-equipment mechanic.

Related Manuals for the Fiat Hitachi Fleet

If you work on more than one model, check these companion documents:

• Fiat Hitachi EX1200-5D User Manual – OEM Operator’s Guide for Excavator – 337 pages of operator-level specs.
• Fiat Hitachi 850-3 / 870H-3 Training Manual – 76 Pages – a condensed training guide for the smaller loader line.
• Fiat Hitachi 250-3, 280-3, 350-3 Training Manual – 384 Pages – covers three models with common hydraulic systems.

Is this manual in English?

No. The manual is the original Italian factory publication.

How do I use torque specs from an Italian manual?

Torque values are universal. The tables use metric units. Convert to imperial if needed, but the numbers are from Fiat Hitachi engineering. Do not mix with aftermarket specs. Always use the factory values listed in the ‘TABELLA COPPIE DI SERRAGGIO’ section. I’ve seen guys cross-thread a final drive because they used a generic chart. Don’t be that guy.

You need the real factory data to do this job right. That 337-page binder gives you everything the factory techs had. No substitute. Access the Factory Manual now.