47RE vs 48RE: Which One Is in Your Cummins and What Makes Them Different

If you own a Dodge Ram diesel from 1994 to 2007, your transmission is either a 47RE or a 48RE — both 4-speed Dodge automatics built behind the 5.9L Cummins. They look almost identical. They're not. And buying parts for the wrong one is one of the most common Cummins owner mistakes.

Here's how to tell which one you have, what's different, and how to build either one for the kind of power Cummins guys actually run.

The short answer

  • 47RE: 1994-2003 Cummins Ram applications, 2500/3500
  • 48RE: 2003 (mid-year) through 2007 Cummins Ram 2500/3500 with the 5.9L 24-valve high-output engine

The 48RE is essentially a strengthened 47RE. Same case, same general architecture, beefier internals for the 305+ HP Cummins of that era.

Year-by-year breakdown

47RE production

- 1994-2002 model year Rams with 5.9L Cummins - 2002-2003 with 24-valve engines making 245-250 HP - Replaced the earlier 47RH (hydraulic, no electronic torque converter control)

48RE production

- 2003 mid-year onward when Cummins jumped to 305 HP common-rail - 2003-2007 all Cummins-equipped 2500/3500 Rams - Discontinued when the 6.7L Cummins arrived with the 68RFE/Aisin AS68/69RC

How to identify which one you have

Method 1: Year + engine

Easiest. If your truck is 1994-2002, it's a 47RE. If it's 2004-2007, it's a 48RE. The 2003 model year is split — early production got 47RE, mid-year and later got 48RE with the new common-rail Cummins.

Method 2: Look at the case

- 47RE: has a fluid temperature sensor port on the right side of the case - 48RE: has the temperature sensor in the same general area but with a different connector pinout

Not the easiest way to tell from a quick visual.

Method 3: Drain pan inspection

The 47RE and 48RE both use the same pan with 14 bolts. Pan alone doesn't distinguish them.

Method 4: Solenoid pack and TCM

- 47RE: uses earlier 4-solenoid configuration with mechanical governor pressure - 48RE: uses 5-solenoid configuration with electronic governor pressure control

If the truck has a temp sensor wire AND a governor pressure transducer wire on the case, it's a 48RE.

Method 5: Most reliable - case tag

Stamped tag on the right (passenger) side of the case has the model number. Look for "47RE" or "48RE" specifically.

What's different inside

The 48RE strengthened these areas vs the 47RE:

Direct clutch pack

- 47RE: 4 friction plates - 48RE: 5 friction plates (more clamping force, more torque capacity)

Overdrive clutch

- 47RE: 4 plates - 48RE: 5 plates (same upgrade pattern)

Input shaft

- 47RE: standard splines - 48RE: stronger material spec, slightly larger spline major diameter

Output shaft

- 47RE: stock spec - 48RE: heavier-duty material

Forward sun gear

- 47RE: stamped - 48RE: forged (more durable for diesel torque)

Governor pressure control

- 47RE: mechanical governor + electronic control via TCM - 48RE: fully electronic governor pressure transducer (more precise shift control)

Valve body

- 47RE: 4-solenoid VB - 48RE: 5-solenoid VB with revised circuits for the electronic governor

What parts interchange

Cross-interchange (47RE ↔ 48RE)

- Pan and pan gasket (same 14-bolt pattern) - Filter (same filter for both) - Most external sensors - Output tail housing - Most case hardware

48RE-only (won't fit 47RE)

- 48RE-specific valve body (different pickup circuits) - 5-plate clutch sets (won't fit 47RE input drum) - Governor pressure transducer - 48RE TCM/wiring harness

47RE-only (won't fit 48RE)

- 47RE valve body (missing the electronic governor connections) - 4-plate clutch sets (smaller stack height) - 47RE mechanical governor assembly

Common failures and what to fix on rebuild

47RE failures

1. Overdrive direct clutch burn — chronic issue under tuning or towing. Upgrade to 5-plate setup (requires drum modification). 2. Front pump bushing wear — common on high-mileage units. 3. Torque converter shudder — TCC clutch wear from PWM apply heat cycling. 4. Governor pressure solenoid failure — leading electronic failure. 5. Valve body apply circuit wear — Sonnax bore correction kits address this.

48RE failures

1. Direct clutch burn — same as 47RE but at higher torque levels. 5-plate stock setup is the baseline; performance builds use 6-plate. 2. Wave plate cracking in the overdrive section — wave plate upgrade required. 3. TCC shudder — same converter clutch issue. Performance converters address it. 4. Governor pressure transducer failure — electronic component, single-point failure. 5. TCM software glitches — Cummins guys often replace TCM with HD-spec aftermarket.

Building either for performance

Built 47RE for moderate Cummins tuning (300-400 HP, 700-800 ft-lb)

- Quality master rebuild kit (Alto Red Eagle frictions) - 5-plate direct clutch upgrade (requires 48RE-spec drum or modified 47RE drum) - Sonnax billet input shaft - Sonnax valve body bore correction kit - TransGo HD shift kit - Upgraded torque converter (BD, ATS, Goerend) - External cooler (large, 30K+ GVW) - About $2,500-3,500 in parts

Built 48RE for serious Cummins (450+ HP, 900+ ft-lb)

- Master rebuild kit with HD frictions (Alto Power Pack) - Billet input shaft and input drum - 6-plate direct clutch - 5-plate forward (stock is 5) - Goerend or ATS triple-disc converter - Sonnax wave plate replacement - Sonnax valve body kit + performance shift kit - HD output shaft - Large external cooler - About $3,500-5,500 in parts

Built 48RE for sled pulling or extreme HP (600+ HP)

- All of the above, plus: - Billet output shaft - Billet flexplate - Triple disc converter with custom stall - Inferno or competition-grade pump kit - Approximately $5,500-8,500 in parts - Add fully manual valve body or paddle shifter setup for race use

Fluid

Both use ATF+4 (Mopar MS-9602). Do not substitute Dexron or Mercon — different friction modifier package, will cause shudder and accelerated wear.

Service interval: every 30,000 miles for tuned/towed trucks. 50,000 for stock-power daily drivers.

Capacity: ~17 quarts total, ~8 quarts in the pan.

Cooling

Both run hot under load. Stock cooler is marginal at best. Add external 30K-40K GVW cooler for any towed or tuned Cummins.

What about the 68RFE?

The 68RFE replaced the 48RE in 2007 when the 6.7L Cummins arrived. It's a 6-speed (not a strengthened 48RE) with completely different internals. Don't confuse the two — 47RE/48RE parts don't fit the 68RFE.

Quick decision matrix

  • Stock power, daily driver: rebuild whatever you have with quality parts
  • Tuned to 400+ HP: upgrade direct clutches and converter regardless of model
  • Tuned to 500+ HP with frequent towing: build heavy or convert to manual VB
  • Race or sled pull: full custom build with paddle shifter, billet drivetrain
  • Truck more than 250K miles: preventative full rebuild before failure

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Need 47RE or 48RE parts? Shop our 47RE catalog and 48RE catalog. Rebuild kits, performance frictions, billet upgrades, valve body kits, and converters from BD, ATS, Goerend, Sonnax, and Alto. Free shipping over $70. Same-day ship in-stock.

Related guides:
- 68RFE rebuild guide
- How to identify your transmission
- Transmission fluid guide