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The 45RFE (1999 on) and 545RFE are Chrysler's electronically controlled five-speeds found in Ram 1500s, Dakotas, Durangos, Grand Cherokees, Commanders and Liberty-era Jeeps with the 3.7, 4.7 and 5.7 engines. Unlike the older RE units, there is no TV cable or hydraulic shift logic. The transmission controller runs every clutch through six solenoids and reads back pressure switches to confirm each apply happened. All of that lives in one part: the solenoid and pressure switch assembly, usually called the solenoid pack.
When the controller sees a solenoid circuit fault or a pressure switch that does not agree with what it commanded, it drops into limp mode. That is the call that sends most RFE owners shopping.
What Is in the Pack
- Six solenoids: Underdrive (UD), Overdrive (OD), 2nd clutch (2C), 4th clutch (4C), Low/Reverse and converter clutch (LR/CC), and the Multi-Select (MS) solenoid.
- Pressure switches that report which clutch circuits are actually pressurized.
- The electrical connector that plugs through the case to the main harness.
Because solenoids and switches are one assembly, you replace the pack, not a single solenoid.
Codes That Point at the Pack
| Code | Meaning | Check First |
|---|---|---|
| P0750 | LR solenoid circuit | Connector at case, harness chafe near the crossmember |
| P0755 | 2C solenoid circuit | Same |
| P0760 | OD solenoid circuit | Same |
| P0765 | UD solenoid circuit | Same |
| P0770 | 4C solenoid circuit | Same |
| P08xx pressure switch codes | Switch reading does not match command | Fluid level and condition before condemning the pack |
If several solenoid codes set at once, check solenoid supply voltage first. The transmission control relay feeds all six. A failed relay or poor ground throws a handful of codes that look like a dead pack.
Picking the Right Part
Solenoid packs changed over the production run. Early 45RFE units (roughly 1999-2003) used a different connector from later ones, so match the plug and the part number stamped on your old pack. Common cross references include 68002342AD, 5170877AA and 52119435AB.
| Option | Best For |
|---|---|
| Solenoid pack and filter service kit | Healthy transmission with a failed pack. Includes both the pan filter and cooler return filter. |
| 45RFE pack and filter kit, 1999-2003 black plug | Early 45RFE trucks with the original connector. |
| 545RFE solenoid kit | Pack only, when you already have filters on hand. |
| Complete valve body with solenoid pack | High mileage, burnt fluid, or shift complaints that persist after a pack. Remanufactured and function tested. |
Browse the full range: 45RFE parts · 545RFE parts
Install Notes That Prevent a Comeback
- Inspect the pan. Fine gray paste is normal wear. Brass flakes or clutch material means the pack is not the whole story.
- Replace both filters. The RFE has a pan filter and a cooler return filter. A plugged return filter starves lubrication and cooling. The 45RFE/545RFE filter kit matches 4WD pans.
- Clean the connector. Fluid wicking through the case connector corrodes pins. Look at both sides before plugging in the new pack.
- Torque the valve body and pack bolts to spec. Uneven torque warps the mating surface and causes pressure switch faults.
- ATF+4 only, then clear codes and run the quick learn with a scan tool. Drive it gently for the first few cycles while adaptives settle.
Pack, Filter Kit, or Complete Valve Body
If the valve body is healthy, a solenoid pack and filters fix it. If it is not, a complete valve body with the pack installed saves a second teardown. Core Transmission Parts carries the rebuild side.
Shop RFE Solenoid Packs → Core Transmission Parts →FAQ
Is the 45RFE solenoid pack the same as the 545RFE?
The hardware family is shared and many packs are listed for both, along with the 65RFE, 66RFE and 68RFE. The difference between a 45RFE and 545RFE is mostly in how the controller uses the gears. Buy by part number and connector, not by the badge on the truck.
Do I have to remove the valve body to change the solenoid pack?
On the RFE units the solenoid and pressure switch assembly mounts to the valve body inside the pan. Plan on dropping the pan and removing the valve body to get it out cleanly.
Do I need a scan tool after replacing it?
Yes. Clear the codes and run the quick learn procedure so the controller relearns clutch volumes. Skipping it leaves harsh or flared shifts that look like the new part is bad.
What fluid do 45RFE and 545RFE use?
ATF+4. Fill to the dipstick with the engine running and the fluid at operating temperature.