The Mopar 45RFE (1999-2002) and 545RFE (2002-2013) are 5-speed automatics used in millions of Jeep Grand Cherokees, Dodge Rams, Durangos, Dakotas, Aspens, and Commanders. Despite the model names, the 45RFE is actually a 4-speed with "alternate 2nd" gear, and the 545RFE is the true 5-speed evolution.
If you own one and it's getting tired, here's the rebuild guide.
45RFE vs 545RFE basics
45RFE (1999-2002)
- 4 forward speeds + alternate 2nd - Hydraulic + electronic control - Used behind 4.7L and 5.7L Hemi - About 250 ft-lb input torque rating stock - Found in Grand Cherokee WJ, Dodge Dakota, Dodge Durango (early)545RFE (2002-2013)
- True 5 forward speeds - Electronic control with TCM - Used behind 4.7L, 5.7L Hemi, 6.1L SRT - About 330 ft-lb input torque rating stock - Found in Grand Cherokee WK/WK2, Commander, Durango, Ram 1500, Aspen, DakotaThe 545RFE was upgraded throughout production. Later units (2007+) have stronger internals than early ones.
Common failures
1. Solenoid pack failure (most common)
The solenoid pack is the leading 45/545RFE failure. Mopar made several revisions trying to fix it, but the basic problem — heat + electrical wear — persists.Symptoms: harsh shifts, slipping, limp mode, multiple DTCs (P0750-P0770 range)
Fix: Mopar updated solenoid pack ($300-500), 4-6 hours labor
2. 2-4 clutch pack burn
The 2-4 clutch carries a lot of work in tow vehicles. Burns out around 100-150K miles.Symptoms: slipping in 2nd, harsh 2-3 shifts, eventual no-2nd
Fix: full 2-4 clutch pack replacement during rebuild
3. Overdrive clutch wear
OD clutch carries 5th gear in 545RFE. Wears faster in tow vehicles.Symptoms: slipping in 5th, no OD lockup
Fix: OD clutch pack replacement
4. Pressure regulator valve wear
PR valve bore wears in the aluminum case.Symptoms: harsh shifts, slipping, codes for low line pressure
Fix: Sonnax PR valve kit (about $150 in parts)
5. Valve body bushings
Multiple bores in the valve body wear over time.Fix: Sonnax bore correction kits + bushings + new valves
6. Cracked direct clutch drum
Under heavy use or tuning, the direct clutch drum can crack. Common on tuned Hemi applications.Fix: Sonnax billet direct drum replacement ($400-600)
Rebuild kit recommendations
Stock Grand Cherokee 4.7L or 5.7L (daily driver)
- Master rebuild kit with Alto frictions - All steels - Solenoid pack (Mopar) - All bushings and seals - Filter and pan gasket - Stock-style torque converter - Cost: $1,200-1,700Towing Ram 1500 5.7L Hemi
- All of the above - Sonnax PR valve kit - TransGo HD shift kit - Larger external cooler (separate purchase) - Raybestos Stage-1 frictions in 2-4 clutch - Cost: $1,600-2,200Tuned Hemi 5.7L or 6.1L (450+ HP)
- All HD parts - Sonnax billet direct drum - Custom torque converter (Edge, ATS, BD) - Performance valve body - HD output shaft - Cost: $2,500-3,800Towing/Hauling SRT Hemi or built application
- Maximum HD kit - Billet input shaft and direct drum - Triple-disc performance converter - Heavy external cooler - Cost: $3,000-4,500Fluid
ATF+4 (Mopar MS-9602). Do not substitute Dexron or Mercon — different friction modifier, causes shudder and accelerates wear.
Capacity: about 14 quarts total, 5-6 quarts in pan.
Service interval: 30,000 for tuned/tow, 50,000 for normal use.
Things that wreck a 45/545RFE early
1. Wrong fluid
Putting Dexron or generic ATF in a Mopar trans is the most common owner mistake. Causes immediate shudder and clutch wear.2. Hot operation without cooler
Stock cooler is marginal in tow trucks. Heat above 230°F destroys ATF+4 friction modifier and damages clutches.3. Tuning without trans support
Putting a hot tune on a 5.7L Hemi and towing with stock trans = burned clutches in 30-50K miles.4. Skipped service
Mopar "lifetime fill" claims for these are aggressive marketing. Reality: every 30-50K with fresh ATF+4.What about the 65RFE and 66RFE?
The 65RFE (2012+) and 66RFE (2012+) are 6-speed evolutions of the 545RFE platform. They share many internals with the 545RFE but added a 6th gear and revised electronics.
For 6.4L Hemi truck applications, the 66RFE is the trans. The 545RFE is for older applications.
68RFE vs 545RFE — completely different
The 68RFE (2007+ Cummins) is NOT related to the 45/545RFE family. The 68RFE is a heavier-duty 6-speed designed specifically for diesel applications. Different transmission, different parts.
If you have a Cummins-equipped Ram (2500/3500 diesel), you have a 68RFE, not a 545RFE. Different rebuild kits, different everything.
What kills the 545RFE in the long run
For trucks that see 200,000+ miles, the typical 545RFE death progression:
1. Solenoid pack codes (around 100-120K) — fix one
2. Harsh shift complaints (around 130-150K) — valve body work
3. Slipping in 2nd or 5th (around 150-180K) — full rebuild
4. Total failure (around 200K+) — replace or rebuild
Every step gets more expensive. Doing a full preventative rebuild at 130-150K is often cheaper over the long term than chasing individual failures.
Cost summary
Daily driver rebuild (parts only)
$1,200-1,700 DIY, plus 25-35 hours of workShop rebuild installed
- Quality independent: $2,800-3,800 - Specialty Mopar shop: $3,500-4,500 - Chain shop: $3,200-4,500Reman swap
- Quality reman 545RFE installed: $3,200-4,200 - Often includes 36-month warrantyFor Grand Cherokees and Rams that aren't worth more than $5,000-8,000, the rebuild is borderline economical. For trucks worth $10,000+, definitely rebuild.
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Need 45RFE or 545RFE rebuild parts? Shop our 45RFE catalog and 545RFE catalog. Master kits, Sonnax billet drums, Mopar solenoid packs, Alto frictions. Free shipping over $70. Same-day ship in-stock.
Related guides:
- 68RFE rebuild guide (Cummins applications)
- 47RE vs 48RE comparison
- Transmission fluid guide