Chrysler 48RE 4-Speed Automatic

Paired with: Dodge Ram 2500-3500, 24-valve Cummins (high-output)

Introduced behind the high-output 24-valve Cummins as the 47RE's stronger successor, sharing the same gear ratios but built heavier and stronger. It remained the standard automatic through the end of the third-generation Ram's Cummins run before the 6.7L's 68RFE arrived.

Strengths

• Heavier and stronger than the 47RE it replaced, while sharing the same proven gear ratios.
• A long aftermarket support history exists for building it to handle higher power, since it remained a go-to platform for diesel performance work for years after production ended.

Known weaknesses

• The overdrive section can still fail under heavy power, though it is more robust than the 47RE's by design.

  Note: An overdrive rebuild kit is the standard preventive upgrade for towing or added power.

• A broken band is a common, well-documented failure on a high-mileage unit.

  Note: Address at the first sign of harsh or delayed shifts rather than waiting for full failure.

• The stock input shaft is a weak point at increased power, towing weight, or in performance use; it can break or twist and damage the converter and pump.

  Note: A one-piece billet (300M) input shaft is the standard upgrade beyond stock power.

Sources

• Chrysler/Dodge 48RE Transmission Specs & Ratios (DieselHub) (accessed 2026-09-22)
• The 47 & 48RE Remain Go-To Transmissions in Diesel Performance (Engine Builder Magazine) (accessed 2026-09-22)