48RE Transmission Problems and Replacement in Edmonton

The 48RE is the four-speed automatic behind the 5.9L Cummins in 2003 to 2007 Ram 2500 and 3500 trucks. Those trucks are still all over Alberta because the engine just keeps going. The transmission is usually the weak link, and with these trucks now roughly 19 to 23 years old, plenty are running on a worn-out original or a tired old rebuild.

Here's what to watch for and how to decide what to do when it starts slipping.

Which trucks have the 48RE?

• 2003 to 2007 Ram 2500 and 3500 pickups with the 5.9L Cummins and an automatic transmission.

• Some early 2003 trucks still have the older 47RE. Your VIN or the transmission tag tells us which.

• Starting in 2005, the throttle valve is controlled by an electric actuator instead of a throttle cable.

Warning signs of a failing 48RE

• No overdrive, or slipping when it shifts into 4th.

• Torque converter won't lock up: RPM sits high on the highway, fuel mileage drops and the transmission runs hot.

• Harsh, late or soft shifts, or flaring between gears.

• Won't upshift, or seems stuck in one gear.

• Slipping or overheating while towing.

• Dark or burnt-smelling fluid.

Why 48RE transmissions fail

Overdrive and converter clutch wear

Overdrive clutch failure and torque converter lockup problems are the most common 48RE complaints. Both get worse with heat, heavy towing and old fluid.

Governor pressure solenoid and sensor

The 48RE relies on a governor pressure solenoid and sensor to shift correctly. When they fail, you get erratic shifts or no upshifts, which can be mistaken for internal damage.

Bands out of adjustment

The 48RE uses bands that need periodic adjustment. When adjustments get skipped, the bands slip, wear and eventually take other parts with them.

Throttle valve actuator (2005 and later)

On later trucks, a faulty throttle valve actuator or its wiring can cause shift complaints that look like a failing transmission. It's one of the first things worth checking.

Added power

Tuned 5.9s put more torque through the transmission than it was built for. The stock torque converter, input shaft and flexplate are known weak points once power goes up.

Is a 20-year-old truck worth a new transmission?

Often, yes. A 5.9 Cummins truck with a healthy engine and a solid frame holds its value, and replacing a worn-out transmission is usually cheaper than replacing the truck. The honest answer depends on the rest of the truck, so we look at the whole picture and tell you if something else makes the repair a bad investment.

We diagnose before we quote. A governor sensor, actuator, wiring fault or band adjustment can sometimes fix the problem without pulling the transmission. If the clutches or converter are done, a new or remanufactured unit is usually the more dependable choice.

3-year, 100,000 km warranty on new and remanufactured transmissions

Every new or remanufactured transmission we install comes with a 3-year, 100,000 km warranty. On a truck this age, that's a lot more peace of mind than a used unit with an unknown history.

How to keep a 48RE healthy

• Change the fluid and filter on schedule and adjust the bands at the same time.

• If you tow, a transmission temperature gauge is worth adding if your truck doesn't show one.

• Let the truck warm up on cold mornings before you load it up.

• If you're adding power, upgrade the transmission and converter to match.

48RE questions we hear

Is the 48RE better than the 68RFE?

They're built for different jobs. Many diesel builders like the 48RE for high-power trucks because it's simple and responds well to upgrades. The 68RFE has more gears and better highway manners. For a stock work truck, both do the job if they're maintained.

Can I keep driving with no overdrive?

You can usually limp it to a shop, but driving on a slipping transmission spreads damage and heat. The sooner it's looked at, the more options you have.

Do you work on fleet trucks?

Yes. See our fleet maintenance page for business accounts, priority scheduling and monthly invoicing.

Get it checked in south Edmonton

Big Toy Shop works on all makes and models, including heavy-duty diesel trucks. We diagnose first, explain what we found, and give you a straight answer on whether your 48RE needs a repair or a replacement. Already have a quote from another shop or dealer? We'll give you a free second opinion.

Find us at 8315 Argyll Road NW. Book online, visit our auto repair page or call 780-298-2797.