The 48RE is the heavy-duty four-speed automatic used behind the 5.9L Cummins in Dodge Ram 2500 and 3500 trucks from roughly 2003 to 2007. The most commonly reported 48RE problems are late, soft or harsh shifts from transmission throttle valve actuator (TTVA) faults, governor pressure problems that stop upshifts, slipping in overdrive, torque converter lockup complaints and overheating under heavy load. Bands that need periodic adjustment are another frequent cause of slipping.
Common 48RE problems
TTVA problems
The 48RE uses an electronic transmission throttle valve actuator in place of the throttle valve cable used on the earlier 47RE. The throttle valve sets line pressure and shift timing with engine load, so a failing or miscalibrated TTVA causes late or early shifts, soft or harsh shifts and slipping. Check codes and the actuator before suspecting internal damage; see 47RE vs 48RE.
Governor pressure problems
RE-family transmissions use a governor pressure solenoid and sensor to control upshifts. When they fail, the transmission may not upshift, shift erratically or hold a low gear; see transmission solenoid symptoms.
Overdrive slipping
Slipping or flaring into fourth gear under load is a classic heavy-duty complaint, often tied to heat, low fluid or wear in the overdrive section; see P0734 and transmission slipping.
Band adjustment
The RE transmissions have front and rear bands that need periodic adjustment as part of maintenance. Bands that are out of adjustment cause slipping and harsh shifts, and adjusting them during a fluid service is cheap insurance.
Converter lockup and overheating
Lockup complaints and high fluid temperature are common on trucks that tow, especially with added power; see bad torque converter symptoms and transmission cooler.
Is the 48RE a good transmission?
Left unmodified behind a factory-power 5.9 Cummins and maintained regularly, many 48REs last a long time. Their reputation suffers when trucks tow heavy without a cooler, run with bands out of adjustment or gain significant engine power, because the overdrive section and converter take the most stress. Upgraded units are built specifically for those uses.
48RE fluid and maintenance
Chrysler specifies ATF+4. Change the fluid and filter on the severe-service schedule if you tow, adjust the bands at the same time, and keep the cooler clean. See how often to change transmission fluid.
Repair or replace a 48RE?
The TTVA, governor parts, bands and valve body are repairs; burnt clutches and a worn overdrive mean a rebuild or replacement. Our StreetMonster 48RE is $4,099.00 and the SportMonster 48RE is $5,594.95 for hard use and added power, both with a torque converter; see our 48RE transmissions and, for earlier trucks, the 47RE and 46RE pages.
More guides: 48RE vs 68RFE · 47RE problems · how long a 48RE lasts.
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