Rancho RS55005 RS5000X Rear Shock Absorber for 72-93 Dodge W-Series Ramcharger

Vehicle Fitment

• 1972-1974 Dodge W100 Pickup (4WD)
• 1972-1974 Dodge W200 Pickup (4WD)
• 1975-1989 Dodge W100 (4WD)
• 1977-1993 Dodge W150 (4WD)
• 1975-1980 Dodge W200 (4WD)
• 1981-1993 Dodge W250 (4WD)
• 1975-1980 Dodge W300 (4WD)
• 1981-1993 Dodge W350 (4WD)
• 1976-1993 Dodge Ramcharger (4WD)
• 1974-1981 Plymouth Trailduster (4WD)

Fitment Notes

• This is the rear shock absorber for the listed Dodge W-Series, Ramcharger, and Plymouth Trailduster 4WD platforms. It is not the front shock for these vehicles - verify position before ordering.
• The RS55005 is compatible with stock height through 4-inch rear lift applications on these platforms. It is commonly paired with different front shock part numbers depending on the front lift height being run. Verify your front lift height and cross-reference the appropriate front shock part number separately.
• Factory shock mounting hardware is reused for installation. All necessary washers, bushings, and nuts are included with the shock.
• Sold individually - order two units for a complete rear pair.

Features

• Cross Tuned technology with Progressive Engagement Valving (PEV) - the RS5000X's defining engineering advancement over the original RS5000; the patented PEV system uses eccentric discs in the valve shim stacks that engage at lower piston velocities and frequencies before the main valving stack fully opens; this provides early fluid flow at the beginning of the shock's compression stroke, reducing the sharp initial impact transmitted to the chassis when the tire contacts a pothole, trail obstacle, or washboard surface; as piston velocity increases, the valving transitions progressively to its full damping rate, providing a controlled, graduated damping response across the full range of shock input velocities rather than the more abrupt transition of conventional fixed-disc valving
• Compression Control Valve - a separate custom-tuned compression valve regulates the fluid transfer rate during the compression phase of the shock stroke; this valve is calibrated specifically for each vehicle application's weight, geometry, and intended use, allowing the RS5000X to manage fluid flow without disc flutter - a condition where the valve disc oscillates rapidly under certain input frequencies, producing inconsistent damping response and an associated harshness in the ride; controlling fluid transfer without disc flutter maintains consistent shock motion control through varying terrain
• Nitrogen gas pressurization at 150 PSI - the shock is charged with nitrogen gas at 150 PSI to separate the gas charge from the hydraulic fluid in the twin-tube reserve chamber; the high-pressure nitrogen charge suppresses aeration and foaming of the fluid under rapid compression cycling, which would otherwise cause the fluid's viscosity to drop and the damping force to fade; consistent gas pressurization maintains the shock's rated damping performance even during sustained off-road use where the shock is cycling rapidly and generating significant heat
• Twin-tube design with 2.25-inch reserve tube - the larger-diameter reserve tube provides greater fluid volume than standard twin-tube designs, which translates directly to lower operating temperatures; greater fluid volume absorbs the same amount of thermal energy with less temperature rise, keeping the fluid's viscosity more consistent during extended off-road use; the 2.25-inch reserve tube is a meaningful upgrade over the smaller bodies used in economy shock designs that target the same vehicle applications
• 16mm nitro-carburized piston rod - the piston rod is surface-hardened through a nitro-carburizing process before chrome plating; this creates a harder surface layer that resists scratching and scoring from grit entering the upper seal area; on classic off-road platforms like the W-Series and Ramcharger that frequently operate in dusty, muddy, or sandy conditions, piston rod surface hardness is critical to seal longevity and preventing the rod surface degradation that leads to oil weeping
• 35mm sintered iron piston with fluon band - the larger 35mm piston diameter provides greater surface area for the valving discs to act upon, improving the precision and consistency of the damping response; the fluon-banded outer diameter of the piston provides low-friction guidance within the shock body, reducing stick-slip behavior at piston initiation that causes the jarring harshness felt over small pavement irregularities
• Low-friction, self-lubricating seal - the upper rod seal is formulated with self-lubricating compounds that maintain consistent friction over the seal's service life without requiring periodic lubrication; lower seal friction at the rod reduces the force threshold for shock initiation, improving small-bump response and ride quality on paved surfaces
• Polyurethane rebound bumper and rubber bushings - the polyurethane rebound bumper absorbs energy at full shock extension, preventing metal-to-metal contact and the associated impact transmitted to the chassis at the limit of travel; rubber bushings at both mounting ends provide controlled compliance in the suspension geometry
• Polyvinyl protective boot - the accordion-style boot covers the exposed piston rod above the upper seal to protect it from direct mud, rock chip, and debris contact; the W-Series and Ramcharger rear suspension geometry exposes the shock rod to significant debris thrown by the rear tires, making boot protection especially valuable on these applications
• Double-welded loops at stress areas - the eyelet mounting loops are double-welded at the points where cyclical suspension loading concentrates stress, providing additional weld material and heat-affected zone at these critical fatigue locations

Specifications

• Part Number: RS55005
• Series: RS5000X
• Position: Rear (driver or passenger side)
• Fitment: 1972-1993 Dodge W-Series 4WD; 1976-1993 Dodge Ramcharger 4WD; Plymouth Trailduster 4WD
• Lift Application: Stock height through 4-inch rear lift
• Internal Design: Twin-tube, gas pressurized
• Gas Charge: Nitrogen, 150 PSI
• Reserve Tube Diameter: 2.25 in.
• Piston Rod Diameter: 16mm (nitro-carburized chrome)
• Piston: 35mm sintered iron, fluon-banded
• Mount Type: Both ends eyelet / loop bushing
• Operating Temperature: -40°F to 248°F
• Quantity: 1 shock (single - order 2 for complete rear pair)
• Warranty: Limited Lifetime

Included Components

• 1x Rancho RS5000X rear shock absorber (RS55005)
• Polyvinyl protective boot (red)
• Mounting bushings, washers, and nuts

Product Description

The Rancho RS55005 is an RS5000X series rear shock absorber for 4WD Dodge W-Series trucks (W100 through W350), the Dodge Ramcharger, and the Plymouth Trailduster, covering production years from 1972 through 1993. It is designed for stock-height through 4-inch rear lift applications on these classic full-size 4WD platforms, making it one of the most broadly applicable shock absorbers in Rancho's catalog for vintage Dodge and Plymouth off-road vehicles.

The RS5000X represents Rancho's engineering upgrade over the original RS5000, centered on the patented Progressive Engagement Valving (PEV) and Cross Tuned technology. The PEV system engages the valving gradually at lower piston velocities - absorbing initial impacts progressively rather than abruptly - and transitions to its full damping rate as input severity increases. This produces a meaningfully more comfortable response over the low-frequency road noise and rough-trail washboarding that are the primary ride quality complaints on these older solid-axle platforms. The nitrogen gas charge at 150 PSI, 2.25-inch twin-tube reserve body, and 16mm nitro-carburized rod provide the thermal management and durability needed for sustained off-road use.

The RS55005 is the rear position shock - confirm the correct front part number for your front lift height separately. Sold individually; two units are needed for a complete rear pair. Factory mounting hardware is reused; all necessary bushings, washers, and nuts are included. Backed by Rancho's Limited Lifetime Warranty.