Swaps the failure-prone plastic accumulator pistons in Chrysler 45RFE, 545RFE, 65RFE, 66RFE and 68RFE units for billet aluminum with a steel support plate.
If your Dodge Ram, Durango, Dakota or Jeep Grand Cherokee, Commander or Liberty with an RFE automatic has started shifting soft, flaring between gears or burning clutches after a rebuild, look at the accumulator pistons. This kit replaces the molded plastic factory pistons in the 45RFE, 545RFE (5-45RFE), 65RFE, 66RFE and 68RFE with five machined billet aluminum pistons. It also includes 20 seals, a steel support plate and the screws to mount it. The same valve body layout is used across the whole family, from 4.7L Jeeps to the 68RFE behind the 6.7L Cummins in the Ram 2500 and 3500.
The RFE units shift clutch to clutch with no bands. Each apply has to be cushioned so the clutch engages firmly and doesn't bang in. The accumulators handle that. Each one is a piston in a valve body bore, held up by springs and closed off by a cover plate. Sonnax notes that the RFE accumulator has no oil pressure behind the piston and relies only on its springs. That makes piston friction critical: any drag or binding in the bore changes how the clutch fills, so it changes the shift.
The factory piston is supported at only one end. Under side load the primary seal sinks into its groove, the piston touches the bore and starts to scuff. The late-model plastic pistons are also brittle. Once the bore is scuffed, the piston no longer moves smoothly, and the shift calibration the controller has learned no longer matches what the hydraulics are doing.
Accumulators are rarely the only problem, so start with codes and line pressure. Read the controller for solenoid, pressure and ratio codes, and compare actual line pressure to desired line pressure on the scan tool. The steps are in our 45RFE pressure control solenoid and line pressure guide. If pressure is in spec but shift quality is still poor, remove the valve body and pull the accumulator cover. Our 45RFE / 545RFE valve body testing guide walks through that teardown. Check each piston for cracks and each bore for scuff marks or a shiny worn band. A slipping overdrive clutch also needs the checks in our 45RFE 3-4 clutch failure guide.
The kit is listed for the Chrysler 45RFE, 545RFE (5-45RFE), 65RFE, 66RFE and 68RFE in Dodge, Jeep and Ram vehicles from 1999 on. That covers the Grand Cherokee, Durango, Dakota and Ram 1500 units and the 68RFE in the heavy-duty Rams. Sonnax lists its own RFE accumulator pistons across that same group of transmissions. Check your transmission ID before ordering, and look at your valve body to confirm it uses the five-piston accumulator layout with a bolted cover. If you are not sure which unit you have, send us your year and VIN and we will confirm it. You can browse everything for this family on the 45RFE / 545RFE parts page.
During a full rebuild, install the pistons along with a 45RFE master rebuild kit so the new frictions get a correctly cushioned apply from the first drive.
| Type | Billet accumulator piston and support plate kit |
| Fits | Chrysler 45RFE, 545RFE (5-45RFE), 65RFE, 66RFE, 68RFE |
| Applications | Dodge, Jeep, Ram 1999-up, incl. 68RFE behind 6.7L Cummins |
| Material | Billet aluminum, hard anodized finish |
| Includes | 5 billet pistons, 20 seals, steel support plate, hardware |
| Replaces | OEM molded plastic accumulator pistons |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for the Chrysler 45RFE, 545RFE (5-45RFE), 65RFE, 66RFE and 68RFE used in Dodge, Jeep and Ram vehicles from 1999 on, including the 68RFE behind the 6.7L Cummins. Confirm your transmission ID, or send us your year and VIN.
Five billet aluminum accumulator pistons, 20 seals, a steel support plate and the mounting screws.
Yes. The accumulators are in the valve body, so the job is done with the pan and valve body removed. You do not need to pull the transmission. Work on the valve body on a clean bench.
Only if the pistons or bores are the cause. Check line pressure and codes first, because a worn solenoid switch valve, a failing pressure control solenoid or a burned clutch pack can feel the same from the driver's seat.
Use ATF+4 only, set the level hot on the dipstick, then run the quick learn with a scan tool so the controller relearns clutch fill with the new pistons.
On a valve body service, check the solenoid pack and its seals and change the filter. On a full rebuild, install the pistons along with a complete master rebuild kit.
