2017 Isuzu NPR Transmission & Axle Gear Ratios
AI-generated reference. Always verify torque values, fluid capacities, intervals, and procedures against the manufacturer's service manual or OEM repair information before performing work. Repairius is not liable for damage from acting on this content without verification.
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Transmission gear ratios
The 2017 Isuzu NPR primarily featured Aisin automatic transmissions, known for their durability and smooth operation in commercial applications. The specific ratios vary depending on the transmission model, which is typically paired with different engine options.
Aisin A465 (A465DPS) 6-Speed Automatic
This transmission was commonly found in NPR models with the 5.2L 4HK1-TC diesel engine.
| Gear | Ratio |
|---|---|
| 1st | 3.750 |
| 2nd | 2.053 |
| 3rd | 1.500 |
| 4th | 1.000 |
| 5th | 0.713 |
| 6th | 0.634 |
| Reverse | 3.541 |
Aisin A460 (A460TIS) 6-Speed Automatic
This transmission was also available and could be found in various configurations, including those with gasoline engines (e.g., 6.0L V8).
| Gear | Ratio |
|---|---|
| 1st | 3.750 |
| 2nd | 2.054 |
| 3rd | 1.375 |
| 4th | 1.000 |
| 5th | 0.708 |
| 6th | 0.600 |
| Reverse | 3.541 |
Available axle ratios
Isuzu NPR trucks offer a range of axle ratios to optimize for either payload capacity, towing, or fuel efficiency. The choice of axle ratio significantly impacts the truck's performance characteristics.
| Ratio | Available With (engine/trim/package) | RPO/Axle Code | Best For |
|---|---|---|---|
| 3.90 | 5.2L Diesel / Standard Duty or Gas 6.0L V8 | Commonly GT4, GT5 | Balanced performance, moderate towing and fuel economy |
| 4.10 | 5.2L Diesel / Heavy Duty or Gas 6.0L V8 | Commonly GT6 | Increased towing and hauling capacity |
| 4.30 | 5.2L Diesel / Heavy Duty | Commonly GT7 | Maximum towing and hauling, but reduced fuel economy |
| 4.56 | 5.2L Diesel / Extreme Duty, sometimes Gas 6.0L V8 | Commonly GT8 | Very heavy hauling/towing, specialized applications |
Note: Axle codes can vary, and it's always best to verify with your specific vehicle's RPO sticker.
How to identify your axle ratio
For 2017 Isuzu NPR models, identifying your axle ratio is typically straightforward. The most reliable method is to check the Service Parts Identification (RPO) sticker.
GM RPO Sticker (for Isuzu-badged vehicles using GM platforms/components): Look for a white sticker, usually located on the inside of the glove box door or the driver's side door jamb. This sticker lists numerous three-character RPO codes. Your axle ratio will be indicated by a code starting with "GT" or "HC". For example:
- GT4: 3.73 (less common on NPR, but possible on other GM trucks)
- GT5: Often 3.90
- GT6: Often 4.10
- GT7: Often 4.30
- GT8: Often 4.56
If you cannot locate the RPO sticker or it
More specs for the 2017 Isuzu NPR
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
Battery Size & Group
Group size, CCA, AGM/flooded, dimensions, reset note.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Fuse Box Diagram & Amperage
Fuse box locations, layout, amps, and what each fuse controls.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
Maintenance & repair guides
2017 Isuzu NPR Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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