| Engine | Ram model years | What it means for owners |
|---|---|---|
| 5.9 12-valve | 1989 to mid-1998 | Mechanical Bosch injection pump; no engine computer running the fuel system. |
| 5.9 24-valve (ISB) | mid-1998 to 2002 | Electronic Bosch VP44 injection pump fed by an in-tank or frame-mounted lift pump. |
| 5.9 common rail | 2003 to 2007 | High-pressure common-rail injection with electronic injectors. |
| 6.7 Cummins | mid-2007 on | Common rail plus diesel particulate filter; later trucks add DEF (urea) aftertreatment. |
Years from Cummins, MotorTrend and DieselHub. Changeover years were split mid-year; confirm with your engine dataplate and VIN.
What makes it different
From mid-1998 through 2002, Dodge used the 24-valve ISB 5.9 with the electronically controlled Bosch VP44 rotary pump. The VP44 relies on the lift (transfer) pump to supply it with fuel, and specialists warn that weak supply pressure is hard on the pump.
Fuel supply is the big one
- Have fuel supply pressure checked, at idle and under load, against the figure in your service information. Specialists such as Diesel Power Products and Pure Diesel Power publish the test procedure.
- Replace fuel filters on schedule and drain water from the housing.
- If you fit a gauge, a fuel pressure gauge is the one most 24-valve owners reach for first. See first mods.
Maintenance focus
Oil, filters, coolant and valve lash follow your manual. See maintenance by category.
Front end
Same 1994 to 2002 chassis as the late 12-valves, so the same front-end parts: the crossover steering kit, steering brace, and for lifted trucks the double adjustable long arms and extreme duty track bar.
Where this comes from
- Cummins: Follow the liter, evolution of the 5.9L to the 6.7L pickup engine
- MotorTrend: 5.9-liter Cummins history and specs
- DieselHub: 5.9L and 6.7L Cummins FAQ
- Blue Chip Diesel: VP44 and lift pump information (PDF)
- Geno's Garage / TDR Buyer's Guide: Fuel transfer pump (PDF)
- Diesel Power Products: How to check lift pump pressure on a 24-valve Cummins
- Pure Diesel Power: Cummins fuel pressure test procedure
Last reviewed 2026-10-19. General information only: your owner's manual and service information come first.