General Information - NKR, NPR, NQR series for 2000 year model
General Information - NHR, NKR, NPR, NQR, NPS, 1999 model year
Heating & Air Conditioning - NHR, NKR, NPR, NQR, NPS, 1994 model year and up
Frame and Cab - NHR, NKR, NPR, NQR, NPS model series 1994 and up
Steering, Suspension, Wheels and Tyres - NHR, NKR, NPR, NQR, NPS series, 1994 model year and up
Propeller Shaft and Axle - NHR, NKR, NPR, NQS, NPS
Brakes - NHR, NKR, NPR, NQR, NPS series, 1994 model year and up
Anti-Lock Brake System
Engine 4J Series 1994 and up (4JB1, 4JB1T, 4JB1-TC, 4JG2) vehicle model: NHR55, NKR55, NPR55, NPR69 engine
Engine 4H (4HF1, 4HF1-2, 4HE1-T, 4HE1-T , 4HG1, 4HG1-T) for NHR, HKR, NPR
Automatic Transmission: 450-43LE, models: NPR, NQR 1999 and up
Manual Transmission and Clutch MBP Series - N-Series, NPR70, NQR70, 1998 model year and up
Manual Transmission and Clutch MSB Series - NHR, NKR, NPR series, 1994 year model and up
Manual Transmission and Clutch MXA Series - NPS, NQR, NKR, NPR series, 1994 year model and up
Cab & Chassis Electrical Workshop Manual (for Right Hand drive vehicle) - vehicle model NHR, NKR, NPR, NQR, NPS
Cab & Chassis Electrical Workshop Manual (for Left Hand drive vehicle) - vehicle model NKR, NPR, NQR
Power Take off - N-Series
Isuzu Trucks N Series
NPR NQR NPS
NKR NHR
Workshop Manual
The Isuzu Isuzu N Series is a medium duty truck produced by Isuzu since 1959. Outside Japan it is known as N series. The range was originally mainly available in Japan and other Asian countries. Australia was another important market for the Isuzu N Series and N series – to the extent that it was manufactured there from the 1970s using many local components. Since the early 1980s, it has also been sold and built in the United States (under the Chevrolet and GMC brand as a W series), and also as the Isuzu N series. North America only receives the wide-cab version. For the common Andinian market (including Chile and Peru), the truck has been assembled in the GM-Colmotores assembling plant in Bogotá, Colombia since 1991, with annual quantities already of 20,000 up to 60,000 units. Local assembly has been increasing because of increasing demand in the Colombian and neighboring markets. It carries "Tecnología Isuzu" (with Isuzu Technology) lettering.In Indonesia, Philippines and several other countries, the Isuzu N Series is not only used as trucks, but also converted into microbuses by local body makers. The lighter four-wheeled models are commonly used as an intercity Angkot (share taxi), as a school bus, or as an employee bus.
The cab-over 2-tonne (4,400 lb) Isuzu N Series (TL221) was originally introduced in August 1959. It was originally only available with the 1.5 litres (1,491 cc) GL150 petrol engine with 60 PS (44 kW). It had single headlights and rear-hinged doors. A longer wheelbase version, on 2,460 mm (97 in) versus the 2,180 mm (86 in) of the regular version, was also available. This carries the TL251 chassis code. In March 1960 a 2-liter diesel engine with 52 PS (38 kW) was introduced (TL121/151), a first for the class in Japan - this was soon followed by diesel models from Isuzu's competitors. In 1962 the engines were updated, and now have 72 and 55 PS (53 and 40 kW) respectively. The chassis codes were changed to TL321/351 for the diesel version, reflecting the installation of the all new DL201 engine. A little later, the chassis codes were reorganized and were now TLG10/11 for the petrol models and TLD10/11 for the diesels. In 1964 the long wheelbase model became the standard version. In 1964 the diesel was also upgraded to the larger 2.2-litre C220 with 62 PS (46 kW). In 1965 the front was redesigned, now with twin headlights.Isuzu ended up offering a very wide variety of bodyworks for the first Elf. There was the original integrated bed, as well as a separate truckbed with dropsides. There was a double-cab version available, as well as special bodywork for dedicated purposes such as a soda truck, a dumper, and a tanker. There was also a "Route Van" model with a glazed rear compartment and seating either three or six, as well as the "Isuzu N Series Bus" which was available in two models from 1960. The Elf Light Bus has integrated bodywork and the long wheelbase and seats 21 passengers (chassis codes BL171/271 for the diesel/petrol) while the Isuzu N Series Micro Bus fit into the very narrow slot between the Route Van and the Light Bus. The Micro Bus originally had the Route Van's bodywork but was more passenger oriented (seating 12 or 15). It carried the TL121/151/21/251B chassis codes, and from 1961 it received its own rear bodywork with bigger glazing. The Isuzu N Series Bus later became its own line, called the Isuzu Journey.
In August 1967 the all-new "Isuzu Light Elf" was added to the existing lineup; this lighter duty version was rated for a 1.25-tonne payload (2,800 lb). It had single round headlights and a KA-series chassis code; it came with the same 1471 cc G150 engine as fitted to period Isuzu Belletts, providing 68 PS (50 kW). This was the first of the second generation Elfs to be introduced, heavier duty models soon followed and replaced first generation variants.
In April 1968 the second generation Elf appeared (TL21/TLD21 series). A walk-through van ("Isuzu N Series Hi-Roof") was also introduced, another first for Japan. In September 1969 the "Light Isuzu N Series" was upgraded to 1.5-tonne (3,300 lb) and now offered a more powerful 1.6-liter engine (G161AB) with 75 PS (55 kW). In October 1970 this part of the range became the Elf 150 while the regular Elf (2-2.5 tonnes) became the Elf 250; the 250 was updated to a 2.4-litre diesel engine. This was combined with the introduction of the heavier duty, 3.5-tonne (7,700 lb) Isuzu N Series 350. This re-shake of the lineup was then followed by the very modern Isuzu N Series Mi-Pack in April 1972. The Mi-Pack was a front-wheel drive model with a flat and low loading floor, only 450 mm (18 in) off the ground. Because of its high price combined with customer reluctance to a front-wheel drive truck it was retired after only a few years on the market. Instead a low-floor model of the Elf 150 was added to the lineup in 1974, featuring small twinned rear tires.
The heavier duty Elf 350 was not immediately replaced but continued in production until the 1980 model year, when in February a 350 model of the third generation Elf was introduced ("350 Wide").
The third generation Elf arrived in June 1975, in Isuzu N Series 150 10 ft., Elf 150 14 ft. 6 wheel and Elf 250 forms are standard. It was nicknamed "Tora-san" after Kiyoshi Atsumi's (a famous Japanese actor) most beloved film character which supposedly looked similar. In January 1977 a 250 Low-Flat model was added, followed in 1978 by a facelift and an altered front grille. In 1979 a 3.3-liter 4BC1 engine of the 2-tonne (4,400 lb) Elf 250 and 350 wide was introduced, called the "Isuzu N Series 250 Super". There was also a "Isuzu N Series 150 Super" version, has the 2.4-liter C240 diesel engine and The 2.8 liter 4BA1 engine for the Elf 150 14 ft. 6 wheel version and Elf 250 wide with heavy-duty transmission.which was usually installed in the Elf 250. In 1978 Isuzu also sold their millionth Elf.In January 1980 the Isuzu N Series was updated to meet Japan's 1979 emissions standards, which was also when the design was changed to accommodate a tilting cab. The Isuzu N Series 250 Wide and 350 Wide were added, with KT and KS chassis codes respectiverly, meaning that the second generation Ef 350 could finally be retired. The Elf Wide has a cabin 1,910 mm (75 in) wide, rather than the 1,690 mm (67 in) cabin used in the TL and KA-series Elfs.
In 1981 the Elf 150/Isuzu N Series 150 14 ft. And Isuzu N Series 250 are standard using the 4BA1 engine and 4BC1 for the Elf 350 wide. range underwent another facelift, with an updated dashboard as well. For the third generation Elf the diesel engines had been modernized for more ease of operation, while the world's then smallest direct injection diesel engine - the 3.3-liter 4BC2 - was also introduced. It arrived in 1982 and replaced the less powerful 4BC1 which had appeared in 1979. In March 1983 the diesel engines were again modified, reflecting new Japanese emissions standards for commercial vehicles. While the third generation Elf was mostly replaced in 1984, the "Route Van" (three- or six-seater van version) continued in production until the early 1990s. With the same bodywork there was also a more habitable bus version available; this was marketed as the Isuzu Journey S and was built on Elf 150 basis (KAD51ZB).
The fifth generation Isuzu Isuzu N Series appeared in July 1993, with more sculpted headlights. The 2.8 4JB1 and 4JB1T are standard on both Isuzu N Series 150 10 ft/14 ft. and Isuzu N Series 250 along with 3.6 4BE1. The non turbo 4JB1 features a new VE Rotary injection pump which increase power to 90ps and euro emission. In May 1995 it received a minor change, including upgraded, cleaner diesel engines. The H-series 4.0-liter 4HE1 and 4.3-liter 4HF1. The 16 ft. Chassis with H-series engine are standard while the 14 ft. Version are still in production. OEM deal with Nissan led to the Elf also being sold badged as a Nissan Atlas and a Nissan Diesel Condor 20/30/35 beginning at this time, followed by the Nissan Atlas Max from 1996 until 2000. The Atlas Max was based on the new, lighter duty Elf 100 (June 1995) which was available with a 2-liter petrol or a 2.5 or 2.7-liter diesel engine.
In the U.S. the Elf was marketed as the Isuzu NPR and Chevrolet/GMC W series, each available with either the 4HE1 4.8-liter turbocharged diesel engine or GM's L31 Vortec 5.7-liter gas engine and 4L80-E Automatic Transmission. The gas engine produced 275 hp (205 kW) to 325 hp (242 kW) at 4600 rpm and 330 lb·ft (447 N·m) to 350 lb·ft (475 N·m) of torque at 2800 rpm.
In May 2004, subsequent to a few minor changes, the Isuzu N Series underwent a more major facelifts with new, larger, trapezoidal headlamps. Another OEM deal was forged at this time and the Isuzu N Series was now also marketed as a Mazda Titan in parallel.
In Malaysia, this truck is manufactured by Heavy Industries Corporation of Malaysia (Isuzu HICOM Malaysia) under the name of HICOM Perkasa, but carrying the Isuzu N-Series Commando badge.
The sixth generation Elf/N series was released in December 2006 (High Cab and Wide Cab) and February 2007 (Regular Cab). By the time the full range was available, the fifth generation Elf was retired. This was also assembled in Colombia (alongside the heavier F series), where it was sold as the Chevrolet NKR, NPR, or NQR. GM began assembling Isuzu trucks in Chile in 1984.The headlight-turnsignal cluster is now configured in the shape of the Isuzu "twin bar" logo, which was used from 1974-1991. In North America, GM sold the Isuzu N series as the Chevrolet and GMC W series until 2009. In 2016, it reintroduced the model as the Low Cab Forward (LCF) series, named simply the Chevrolet 3500, 4500, or 5500, and available with the same gasoline or diesel engines.
Isuzu Motors Limited is a Japanese manufacturer of commercial vehicles, diesel engines, and trucks. The company was founded in 1916 as the Tokyo Ishikawajima Shipbuilding and Engineering Co., Ltd. and began producing vehicles in 1922.
During the 1920s and 1930s, Isuzu primarily focused on producing trucks and buses for the Japanese market. In the post-World War II period, the company began exporting its vehicles to other countries, and expanded its product line to include a wide range of commercial vehicles, including buses, trucks, and construction equipment.
In the 1960s, Isuzu began to focus on diesel engines, and developed a reputation for producing high-quality and reliable diesel engines for various types of vehicles. In the 1970s and 1980s, the company expanded its global presence by opening manufacturing facilities in other countries, such as the United States, and entering into partnerships with other manufacturers.
Isuzu is known for its high-performance diesel engines and commercial vehicles. The company's products are used in a wide range of industries, including transportation, construction, and mining. In recent years, Isuzu has continued to expand its product line to include light-duty trucks, medium-duty trucks, heavy-duty trucks, and buses.
In 2021, Isuzu announced a strategic alliance with Honda to produce electric vehicles and hydrogen fuel cell vehicles, which is expected to enhance the company's position in the EV market. Isuzu continues to invest in research and development to improve its products and reduce emissions. The brand is widely known for its durability and reliability, and it is considered one of the leading brands in the commercial vehicle market.
### Suspension Repair on Isuzu NPR NQR NPS NKR NHR N SERIES
#### Tools Needed:
1. **Jack & Jack Stands** - To lift the vehicle safely.
2. **Socket Set** - For removing bolts and nuts.
3. **Wrenches** - For accessing tight spaces.
4. **Pry Bar** - To help remove stubborn components.
5. **Torque Wrench** - To ensure proper torque settings.
6. **Ball Joint Separator** - For separating ball joints if required.
7. **Spring Compressor** - If replacing coil springs.
8. **Hammer** - For tapping components into place.
9. **Safety Glasses** - To protect eyes from debris.
10. **Gloves** - To protect hands from sharp edges.
11. **Replacement Parts** - Bushings, shock absorbers, springs, and other worn components.
#### Safety Precautions:
- Always work on a flat surface.
- Use jack stands after lifting the vehicle with a jack.
- Wear safety glasses and gloves.
- Ensure the vehicle is in gear or has the parking brake applied.
- Be cautious of any residual pressure in air or hydraulic systems.
#### Step-by-Step Procedure:
1. **Preparation:**
- Park the vehicle on a flat surface and engage the parking brake.
- Gather all necessary tools and replacement parts.
2. **Lift the Vehicle:**
- Use the jack to lift the front or rear of the vehicle as needed.
- Place jack stands securely under the vehicle to support it.
3. **Remove the Wheel:**
- Using a socket set, remove the lug nuts and take off the wheel to access the suspension components.
4. **Inspect Suspension Components:**
- Check for any visible signs of wear or damage on components such as shocks, bushings, and springs.
5. **Remove Old Shocks/Struts:**
- Use a wrench to remove the bolts securing the shock absorbers.
- If necessary, use a ball joint separator to disconnect any components attached to the shocks.
6. **Replace Shock Absorbers:**
- Install the new shock absorbers by aligning them with the mounting points.
- Hand-tighten the bolts before using a torque wrench to tighten them to the manufacturer’s specifications.
7. **Replace Bushings (if necessary):**
- Use a pry bar to remove old bushings carefully.
- Install new bushings by applying lubrication if needed, then pressing them into place.
8. **Replace Springs (if applicable):**
- If replacing coil springs, use a spring compressor to safely compress the spring.
- Remove the old spring and install the new one, ensuring it is seated correctly.
9. **Reassemble:**
- Reattach any components that were removed, including the wheel hub and brakes if applicable.
- Reinstall the wheel and hand-tighten the lug nuts.
10. **Lower the Vehicle:**
- Carefully lower the vehicle from the jack stands using the jack.
11. **Final Checks:**
- Once on the ground, use a torque wrench to tighten the lug nuts to the specified torque.
- Perform a final inspection to ensure all components are secure.
#### Common Pitfalls to Avoid:
- **Neglecting Safety:** Always use jack stands; never work under a vehicle supported only by a jack.
- **Overtightening Bolts:** This can strip threads or damage components; always adhere to specified torque settings.
- **Incorrect Component Installation:** Ensure that all parts are installed in the correct orientation and seated properly.
- **Ignoring Alignment:** After suspension work, a wheel alignment is often necessary to prevent premature tire wear.
#### Conclusion:
Following these steps systematically will ensure a successful suspension repair on the Isuzu NPR NQR NPS NKR NHR N SERIES. Always refer to the vehicle’s service manual for specific torque specifications and part numbers. rteeqp73
Tools & consumables
- Basic: 3/8" and 1/2" drive ratchets, extensions, swivel/U-joint
- Sockets: metric set (10–22 mm common), deep sockets for battery/terminal nuts
- Wrenches: metric open/box end wrenches (10–19 mm)
- Torque wrench (in Nm; 0–150 Nm range)
- Breaker bar and/or 1/2" impact (use cautiously)
- Jack, jack stands or ramps; wheel chocks
- Safety: safety glasses, gloves, hearing protection
- Multimeter (12 V, voltage-drop test)
- Battery terminal puller or pliers
- Insulated jumper leads for bench-testing starter (or a dedicated starter test rig)
- Wire brush, emery cloth, contact cleaner
- Anti-seize compound (light) and dielectric grease for terminals
- Replacement parts: correct Isuzu starter motor assembly (or solenoid and drive if doing partial repair), replacement mounting bolts if corroded, new terminal nuts/boots if damaged, new battery cables if necessary
- Optional: amp clamp for starter current draw test, penetrating oil (PB Blaster), shop light, magnetic tray for bolts
Safety precautions (read before starting)
- Park on level ground, set parking brake, chock wheels. Never work under a vehicle supported only by a jack — use stands.
- Disconnect battery negative cable first and isolate it well; remove or secure positive cable when working near it to prevent shorts.
- Wear eye protection and gloves. Be aware of hot exhaust/engine components.
- If lifting the front of truck, use rated jacks and stands and block wheels.
- Avoid accidental cranking once battery is disconnected. Keep ignition OFF.
- Consult OEM workshop manual for model-specific notes and torque specs.
Overview / location
- On Isuzu N-series models (NPR, NQR, NPS, NKR, NHR) the starter is mounted to the bellhousing at the rear/lower side of the engine (passenger side on many configurations). It may be partially obscured by heat shields, intake piping, or brackets. Access often from under vehicle or by removing splash shield and/or air intake duct.
Step-by-step: removal
1. Prepare vehicle
- Park, chock, set parking brake. Raise front end and support with jack stands if necessary. Disconnect negative battery terminal and secure away from battery.
2. Gain access
- Remove underbody splash shields, heat shields or intake ducts that block starter. Use penetrating oil on bolts if corroded. Note routing of any hoses/electrical for reassembly.
3. Identify wiring
- Locate the main battery cable on the starter (large stud) and the small ignition/solenoid control wire(s). Take photos or mark wire positions.
4. Disconnect wiring
- Remove nut(s) holding main positive cable to the starter stud (hold stud with a wrench if needed) and disconnect small terminal connector(s). Protect terminals from shorting to chassis.
5. Support transmission/engine if required
- On some models the starter also helps locate the transmission; if removing could shift the gearbox slightly, use a transmission jack or support engine/transmission as directed by manual.
6. Remove mounting bolts
- Remove the starter mounting bolts (usually 2 or 3). Use extension and U-joint to reach hard bolts. Use breaker bar if necessary. Keep bolts and any washers in magnetic tray. Note bolt lengths and positions.
7. Extract starter
- Carefully withdraw starter from bellhousing. It can be heavy — lower it slowly to avoid dropping. Inspect flywheel ring gear visible surface for damage while starter is out.
Starter bench test (optional)
8. Bench-test replacement or removed starter
- Secure starter on wood block. Connect battery positive to starter large terminal, ground starter case to battery negative. Briefly connect small solenoid terminal to positive to operate. Starter should spin briskly and extend/engage drive (if equipped). If noisy, slow or fails, replacement required.
Inspection before re-install
9. Inspect and clean
- Clean mating surfaces on engine bellhousing. Inspect starter mounting boss threads; repair if stripped. Check wiring harness and battery cables for corrosion, fraying or high-resistance joints. Replace any damaged parts. Inspect starter pinion and flywheel teeth for wear or missing teeth.
Replacement parts recommended
- New starter assembly (recommended OEM or equivalent)
- New starter mounting bolts if corroded or stretched
- New terminal nuts/insulating boots
- New battery cable(s) if terminals show corrosion or high resistance
- If solenoid only is faulty and compatible, replace solenoid assembly per workshop manual (partial rebuilds less common)
Step-by-step: installation
10. Position starter
- Place starter into bellhousing; align carefully so pinion mesh clears ring gear. Feed wires out of the way.
11. Install mounting bolts
- Start bolts by hand to avoid cross-threading. Tighten progressively and evenly. Torque bolts to OEM specification (consult service manual). Typical starter bolt range: 35–80 Nm depending on model — confirm exact value in manual.
12. Reconnect wiring
- Reattach large battery cable to starter stud and tighten nut securely. Reconnect small control wire(s) and install insulating boots. Apply dielectric grease to terminals to prevent corrosion.
13. Reinstall shields/air ducts
- Refit any removed heat shields, splash pans, and intake ducts. Reconnect any moved sensors or hoses.
14. Reconnect battery and test
- Reconnect negative battery terminal. Crank engine and verify starter engages and starts engine. Listen for abnormal sounds (grind, whine, click).
- If starter clicks but does not crank, test voltage at starter while cranking (should be ~9.6 V+ with heavy cranking) and check for voltage drop on battery cable and ground. Use multimeter voltage-drop test across positive and ground connections (<0.5 V ideally under load).
15. Final checks
- Re-torque mounting bolts after initial run if manual suggests. Clear any fault codes in vehicle system (if triggered) and do a short road test. Re-check for oil leaks around starter area or loose wires.
How each tool is used — brief
- Ratchet/extensions/U-joint: reach and remove starter bolts in tight spaces.
- Breaker bar: break loose stubborn bolts; use carefully to avoid rounded heads.
- Impact gun: speeds removal but use low torque and finish tightening with torque wrench.
- Torque wrench: final tightening to OEM torque prevents distortion/loose fit.
- Multimeter: check battery voltage, voltage drop, continuity of starter control circuit.
- Amp clamp: measure starter current draw (compare to spec; high draw indicates mechanical binding or short; low draw indicates electrical issue).
- Bench test jumper leads: power starter off-vehicle briefly for function check (do not run long without load).
Common pitfalls & how to avoid them
- Forgetting to disconnect battery — risk of short and injury. Always disconnect negative first.
- Stripping mounting bolt heads — use correct socket size, keep wrench square, apply penetrating oil and use breaker bar if needed.
- Cross-threading bolts on install — start bolts by hand.
- Not supporting transmission/engine where required — starter removal can allow slight movement; follow manual.
- Re-connecting wires incorrectly — mark or photo before removal.
- Re-using corroded battery cables/terminals — results in high resistance and starter problems; replace as necessary.
- Using excessive force with impact wrench on starter bolt threads — can stretch or break bolts; torque properly.
- Ignoring voltage-drop testing — replacing starter when the real problem is poor cable or ground is a waste.
- Not checking flywheel ring gear — damaged teeth will damage new starter drive quickly.
- Applying threadlocker if OEM advises against it — consult manual (generally use light anti-seize, not heavy threadlocker).
When to replace vs rebuild
- Replace starter assembly if: slow/no crank, grinding, burned windings, bad solenoid, excessive oil contamination, or when overhauling is not cost-effective.
- Rebuild only if motor and housing are in good condition and parts (brushes, solenoid, bushings) are available and you have bench skills.
Final notes
- Always verify exact torque values and model-specific removal steps in the Isuzu workshop manual for the specific chassis/engine code. Follow safety steps exactly. rteeqp73