- 12-valve / 24-valve
- The two mechanical-era 5.9 Ram Cummins families, named for valves per engine. The 24-valve uses the electronic VP44 pump. More →
- Axle wrap
- Leaf springs twisting under torque so the rear axle rotates and hops. Traction bars resist it. More →
- Common rail
- Injection system where a high-pressure pump feeds a shared rail and electronic injectors. Ram 5.9 from 2003 and all 6.7s. More →
- Death wobble
- Violent front-end shake on solid-axle trucks after a bump, usually traced to worn steering or track bar parts. More →
- DEF
- Diesel exhaust fluid, a urea solution sprayed into the exhaust by the SCR system to cut NOx. More →
- DPF
- Diesel particulate filter. Traps soot and burns it off in regenerations. More →
- Exhaust brake
- Uses exhaust back-pressure, via the turbo on many Cummins Rams, to help slow the truck. More →
- Fifth wheel
- Bed-mounted hitch plate with jaws that lock a trailer kingpin. More →
- GVWR / GCWR
- Gross vehicle weight rating and gross combined weight rating: the maker's limits for the loaded truck, and truck plus trailer. More →
- Gooseneck
- Bed-mounted ball hitch; the trailer coupler drops over it. More →
- Hydraulic lash adjuster
- Self-adjusting valve train part. Cummins says 2019 and later chassis-cab 6.7 engines use them. More →
- ISB / B6.7, ISL / L9
- Cummins engine names: ISB was renamed B6.7, ISL became L9. Common in motorhomes and medium-duty trucks. More →
- Lift pump
- Low-pressure pump that feeds fuel to the injection pump. More →
- Long arms
- Longer front control arms used on lifted link-front trucks to keep geometry and ride. More →
- Radius arm
- One-piece front arm per side, used on Ram HD from 2013 (3500) and 2014 (2500). More →
- Regeneration (regen)
- Burning collected soot out of the DPF at high exhaust temperature. More →
- Track bar
- Link that centers the solid front axle side to side. More →
- Valve lash
- Clearance in the valve train; Cummins calls the adjustment the overhead adjustment. More →
- VP44
- Bosch electronic rotary injection pump on the 1998.5-2002 24-valve. More →
- Weight distribution hitch
- Receiver hitch with spring bars that shift tongue weight forward to the front axle and back to the trailer. More →
- 4BT / 6BT
- Mechanical Cummins B-series four and six popular for engine swaps. More →
Where this comes from
- Cummins: Follow the liter, evolution of the 5.9L to the 6.7L pickup engine
- DieselHub: 5.9L and 6.7L Cummins FAQ
- Blue Chip Diesel: VP44 and lift pump information (PDF)
- U.S. EPA: Diesel particulate filter (DPF) technical bulletin
- Cummins: DEF quality and maintenance (PDF)
- Cummins: 6.7L Turbo Diesel for 2019 Ram chassis cab
- CURT: Gooseneck vs fifth wheel, adapters explained
- Equal-i-zer: About your weight distribution hitch
- NHTSA interpretation 8079: GVWR and vehicle alterations
- Torque King IDN-121: 1994-2013 Dodge Ram 5-link coil spring identification
- DrivingLine: Dodge death wobble, causes and cures
- Carli Suspension: 1994-1998 Dodge extended control arms
- Diesel World: Cummins 4BT 101
Last reviewed 2026-10-19. General information only: your owner's manual and service information come first.