66RFE Planetary 2016, used and ready to install. Fits the 66RFE. Ships fast from the USA.
The 66RFE is the six-speed behind the gas HEMI in Ram heavy duty trucks, and when one of its gearsets wears out you hear it before you feel it: a howl that climbs with road speed, then glitter on the pan magnet, then a gear that will not hold. This is a used 66RFE planetary gear set removed from a 2016 Ram. It is sold as pictured - the photos show the exact carrier, pinions and ring gear you receive - and it is priced for the owner or shop rebuilding a 2014-2018 Ram 2500 or 3500 with the 5.7L or 6.4L HEMI.
Ram's own spec sheets describe the 66RFE as three planetary gearsets, one overrunning clutch and full electronic control. Raybestos describes it as a 545RFE-style case carrying many of the same internals and the gearset of the diesel 68RFE, which is why both units share the same 3.23, 1.84, 1.41, 1.00, 0.82, 0.63 and 4.44 reverse ratios. The transmission applies two clutches at a time to lock or drive different members of the three gearsets, and that combination sets each gear. The gearsets themselves never shift; they just carry torque continuously, so pinion bearings, thrust washers and splines are what wear. Gas HEMI trucks spend a lot of time at high rpm towing campers and equipment, and the heat that comes with that is what dries out pinion bearings.
Gear noise on a 66RFE is often blamed on the wrong part. Pump noise follows engine rpm; gearset noise follows vehicle speed, so note whether the sound changes when you hold road speed steady and let the engine rpm change through a shift. Our RFE pump failure guide explains how to separate the two. Slipping clutches are a more common cause of ratio codes than broken gears, so test pressures and solenoids first using the RFE shift solenoid testing guide, which applies to the shared RFE solenoid design. On teardown, spin each pinion for roughness, check pinion end play, and look for worn sun gear splines and bluing on the carrier.
This gearset came from a 2016 Ram 66RFE, so the closest match is a 2014-2018 Ram 2500 or 3500 with the 5.7L or 6.4L HEMI, including the 3500 chassis cab with the 66RFE. Some 2012-2013 66RFE internals differ from the 2014-on design, and the listing does not identify which of the three gearset positions this carrier came from, so compare it side by side with your original: tooth count, spline count, carrier height and pinion layout. Do not assume a 545RFE or 65RFE gearset is the same part. When in doubt, send us your year and VIN with the order. You will find matching parts in our 66RFE parts collection and the related 68RFE collection.
Any gearset failure sends steel through the cooler, so flush or replace the cooler and clean the case and valve body before reassembly. Set the selective thrust washers to spec and replace any thrust bearing that feels rough. A 66RFE overhaul kit gives you the seals and gaskets for the job, and if the frictions show heat a 66RFE clutch module replaces them at the same time. Fill with Mopar ATF+4 and set the level hot. Since heat is the usual root cause on towing trucks, a 66RFE transmission cooler is cheap insurance for the new gearset.
| Fits | 66RFE 2016 |
| Part type | Planetary |
| Condition | Used |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The gas Ram 2500 and 3500 heavy duty trucks, behind the 5.7L HEMI and, from 2014, the 6.4L HEMI, including the Ram 3500 chassis cab. The 6.7L Cummins trucks use the 68RFE instead.
Raybestos says the 66RFE carries many of the same internals and the gearset of the 68RFE, and both list the same ratios. Always compare the gearset to your original before installing, because individual parts changed over the years.
The listing does not name the position. Compare the photos with the carrier you removed, or send your year and VIN and we will confirm it matches before shipping.
Mopar ATF+4. Set the level with the fluid at operating temperature after the repair.
Worn thrust bearings and washers, the filter, all seals and gaskets, and any heat-damaged clutches. Flush or replace the cooler so debris does not return to the new parts.
