48RE Pressure Control Solenoid 1994-2007

One thing up front: this listing is titled 48RE pressure control solenoid, but the part that ships is a new RevMax 478-604 low/reverse drum for the 47RH, 47RE and 48RE behind the 5.9L Cummins in 1994-2007 Ram 2500 and 3500 trucks. Builders usually go looking for one after opening a transmission that slipped in reverse or had no manual low and finding the inside of the old drum scored, or the overrunning clutch race chewed up.

What the low/reverse drum does in a 47RE or 48RE

The low/reverse drum sits at the rear of the main geartrain. The rear band wraps around its outside, and the race for the overrunning clutch is pressed onto its hub. In first gear in Drive or 2, the overrunning clutch holds the drum so the truck pulls away. In manual low and Reverse, the rear band clamps the drum instead. The drum's inside diameter turns on the overdrive piston retainer hub, so it depends on a steady film of lube oil. RevMax notes the inside of this drum is often scored when cooler flow is low or debris circulates through the cooling system.

Symptoms of a worn drum

• Slipping in Reverse only, which the factory manual traces to the rear band or its drum
• No engine braking or slipping in manual low (1)
• Slip on takeoff in Drive first gear but not in manual low, which points to the overrunning clutch and its race
• Scoring or bluing on the drum's inside diameter or on the outer band surface found at teardown
• Metal and lining debris in the pan after a cooler or converter failure

How to confirm it before you buy

The road test tells you a lot. Note which ranges slip: rear band problems show in 1 and Reverse, overrunning clutch problems in Drive first gear only. Adjusting the rear band through the pan is the first step; if it slips again soon after, the band and drum are worn. Once apart, Chrysler's rule is simple: replace the drum if the clutch race, roller surface or inside diameter is scored, worn or damaged, and never try to press the race off. Our 48RE Cummins transmission problems guide covers the usual failure chain, and the Ram 3500 Cummins shift problems guide covers road-test diagnosis.

Fitment

RevMax lists this drum for 1994-2007 Ram 2500 and 3500 Cummins trucks with the 47RH, 47RE or 48RE. The 47RH covers the early years, the 47RE took over in the mid-1990s and the 48RE arrived in 2003; the low/reverse drum carries across all three. Rebuilt units can contain mixed-year parts, so compare the old drum's spline count and hub height with this one, or send us your year and VIN and we will check. Browse all parts on the 48RE parts page.

Install notes

• Inspect the overdrive piston retainer hub the drum rides on. If its surface is scored, replace it too, or the new drum will wear the same way.
• Install the overrunning clutch first, position the rear band, then slide the drum through the band and onto the hub until it engages the rollers. Fit the thrust washer in its spotface and install the snap ring.
• Fit a new rear band if the old one is glazed or worn thin; the 48RE master rebuild kit covers frictions and seals in one box.
• Adjust the rear band to the spec for your year. The 1998 manual for the 47RE calls for 72 in-lb then 3 turns back, with the locknut at 25 ft-lb.
• Fix the cause. Flush or replace the cooler, because scored drums usually trace back to restricted flow; the 48RE transmission cooler fits 2003-2007 trucks. Refill with ATF+4.

Is this a pressure control solenoid?

No. Despite the listing title, it is a new RevMax 478-604 low/reverse drum for 47RH, 47RE and 48RE transmissions behind the 5.9L Cummins.

Does it come with the overrunning clutch race?

The race is a permanent press fit on the drum hub, and Chrysler says to replace the drum and race as an assembly. Compare the new drum with your old one before installing.

My truck slips only in Reverse. Is it the drum?

It can be. Reverse-only slip points to the rear band, its adjustment or the drum it clamps. Adjust the band first; if it slips again, inspect the band and drum surface.

Why do these drums get scored inside?

RevMax notes scoring usually follows low cooler flow or debris in the cooling system. Replace or flush the cooler and inspect the overdrive piston retainer hub the drum rides on.

What fluid should I use after the repair?

Mopar ATF+4. Chrysler warns that non-specified fluids can cause poor shift quality and converter shudder.

• 48RE Cummins Transmission Problems: Failure Points, Upgrades, and What Actually Breaks
• 48RE Ram 3500 Cummins Shift Problems: Diagnosis and Fix
• 48RE Ram 2500 Cummins Common Problems and Fixes
• 48RE Pump Failure Symptoms and Replacement