68RFE Ram 3500 Cummins Shift Problems: Diagnosis and Fix

A Ram 3500 Cummins with a "shift problem" can mean five different complaints: a flare on the 1-2 or 4-5, a bang on the way down when the exhaust brake is working, a 1-2-1 hunt on a grade, a bind-up that feels like two gears at once, or a truck that leaves from a stop in second. Each one points somewhere different inside the 68RFE, and on a one-ton a few of them have a factory software answer that should be ruled out before anybody pulls a pan.

This is the shift-quality guide for the 3500. If the complaint is a clutch that will not hold under load, use our 68RFE Ram 3500 slipping guide instead. If the truck is stuck in one gear, start with 68RFE limp mode causes.

Recommended 68RFE parts

The parts that fix 68RFE shift-quality problems on a 3500: a solenoid and pressure switch pack for solenoid and pressure switch codes, and a remanufactured valve body (2010-2018 or 2019-up) when the switch valve or regulator bores are worn. Secure checkout.

68RFE Solenoid Kit 2007-2018

$412.98View part

68RFE Valve Body 2010-2018 - Remanufactured 5-Ball, Standard Duty

$405.00View part

68RFE Valve Body 2019-Up - Remanufactured Heavy Duty

$1025.00View part

First, Make Sure It Is a 68RFE

Ram's 2024 Heavy Duty specification sheet lists the 68RFE behind the standard-output 6.7L Cummins (370 hp, 850 lb-ft) in both the 2500 and the 3500. The high-output 6.7L is a 3500-only package and it gets the Aisin AS69RC instead. [1] So "Ram 3500 Cummins" alone does not tell you what is under the truck. Check the build sheet: FCA's recall paperwork identifies the 68RFE by sales code DG7. [3] An Aisin truck has a different valve body, different software bulletins and different failure patterns, and nothing below applies to it.

The same spec sheet gives the 68RFE ratios you will use for every check in this post: 3.23 first, 1.84 second, 1.41 third, 1.00 fourth, 0.82 fifth, 0.63 sixth and 4.44 reverse. The 3500 is offered with 3.73 gears on single and dual rear wheel trucks and 4.10 on the dually. [1]

How the 68RFE Makes a Shift

Every shift-quality complaint on this unit makes more sense once you remember it is a clutch-to-clutch transmission. There are no bands and no one-way clutch doing the timing on upshifts. The TCM releases one clutch and applies the next, and it judges the result from input and output speed.

• 1st: underdrive (UD) plus low/reverse (L/R). ATSG notes the L/R clutch is only on while output shaft speed is below 150 rpm; above that the low sprag carries first. [4]
• 2nd: UD plus 2C. 3rd: UD plus 4C. 4th: UD plus OD (1.00).
• 5th: OD plus 4C. 6th: OD plus 2C.

Two things in the valve body decide whether those swaps are clean. The first is the solenoid switch valve (SSV). Sonnax describes it this way: on the 1-2 shift the switch valve strokes to send fluid to the 2C circuit, on the 2-3 the bore plug strokes up against the switch valve, and on the 3-4 the plug strokes back the other way to feed the OD circuit and hold the switch valve. [6] If that bore is worn, oil leaks between circuits during the exact moment the TCM is trying to time a swap.

The second is adaptive learning. ATSG explains that the TCM adjusts the clutch apply rate as frictions wear, and tracks a Clutch Volume Index (CVI) for each element to optimize clutch-to-clutch timing. [4] Five pressure switches in the solenoid and pressure switch assembly report back when each circuit is charged; they close at 23 psi and open at 11 psi. [4] When a shift goes bad, the TCM is usually reacting to one of those inputs, not inventing the problem.

Complaint 1: Flare on the Upshift

A flare is engine rpm jumping between gears because the off-going clutch let go before the on-coming clutch picked up the load. On a 3500 it is most often heard on the 1-2 or felt as a soft, long 4-5 under a trailer.

Start with software. FCA TSB 18-005-23 (January 12, 2023, also released as Rapid Service Update 23-007) covers all 2022 Ram 2500 and 3500 Cummins pickups. For 68RFE (DG7) trucks the listed improvements include reducing audible engine flare during upshifts and helping prevent premature OD clutch wear, and the DTC list includes P0755 (shift solenoid B) and P0765 (shift solenoid D). [2] For 2019 trucks, TSB 18-066-23 (May 24, 2023) lists "transmission upshift quality enhancements (68RFE only)" and overall shift schedule improvements. [2] Both bulletins call for a Quicklearn after the 68RFE flash, and both require a battery charger holding 13.2 to 13.5 volts during programming. [2] A flash on a sagging battery is how you turn a shift complaint into a no-start.

If the software is current and it still flares, separate a real flare from torque converter slip. GEARS points out that a worn torque converter regulator valve bore can cause excessive TCC slip that is easily mistaken for a 4-5 shift flare, along with harsh TCC apply or release and engine stall at stops. [5] Graph engine rpm against input speed through the shift. If input speed follows the gear ratio and only engine rpm rises, the converter is slipping, not a clutch.

If input speed itself overshoots the ratio math, it is a clutch timing issue. Divide input speed by output speed through the shift and watch how long the ratio sits between gears. Sonnax notes that clutch clearance that is too loose lengthens fill time and causes drag and heat, while clearance that is too tight shortens fill time and can bind. [6] Some professional scan tools display the CVI for each clutch, and a value that keeps climbing points you to the element that is wearing. [6]

Complaint 2: Clunk on Downshift With the Exhaust Brake On

This is the classic fifth-generation complaint: the truck is coasting down to a light with the exhaust brake working, and the 3-2 or 2-1 lands with a bang. FCA TSB 18-066-23 lists "harsh downshift clunk during exhaust brake deceleration" as a customer concern on 2019 Ram 2500 and 3500 Cummins trucks, along with Smart Exhaust Brake operation improvements and improved shift quality in 4LO. [2] The same bulletin lists P0868 (line pressure low) and P0870 (hydraulic pressure test) as 68RFE-only codes it addresses. [2]

The point for a shop: on a 2019 that has never had the PCM updated, the flash is the first repair, not a valve body. After the flash, perform the Quicklearn so the TCM relearns the clutch volumes with the new calibration. [2] If the clunk survives the update and a fresh learn, then look at line pressure and the solenoid switch valve the same way you would for any harsh shift.

Complaint 3: 1-2-1 Hunting on a Grade

Hunting is the TCM changing its mind. TSB 18-005-23 specifically lists 1-2-1 gear hunting on grades under high load in low-traction conditions (rain, snow, ice or dirt) on 2022 68RFE trucks. [2] Wheel spin changes output speed, and the shift schedule reacts to it.

Outside that bulletin, hunting on a 3500 is usually a load-versus-gearing problem. GEARS notes that oversized tires make the 68RFE downshift-sensitive and can push commanded line pressure up to around 225 psi in sixth on a tuned truck. [5] A 3500 on 37s with the original axle ratio, pulling a fifth-wheel, can sit right on a shift point at highway speed. Confirm the tire size is programmed correctly before chasing hydraulics.

Complaint 4: Bind-Up, Second-Gear Starts and P0871

A shift that feels like the truck hit a wall for half a second, a launch in second, or a stored P0871 (OD pressure switch rationality) all point at the same area. GEARS lists P0871, burned OD clutches, second-gear starts and binding on shifts as solenoid switch valve symptoms, and notes that valve body warpage can cause the identical set. [5] Sonnax's switch valve kits are listed against codes 841, 868, 871, 988, 1775 and 1776, wrong-gear and second-gear starts, bind-up and erratic TCC apply. [6]

The test is a vacuum test of the SSV bore and plug, which Sonnax calls a quick, effective way to check this area. [6] GEARS adds a practical warning for the TCC accumulator and regulator bores: they wear egg-shaped, so test at the point of greatest wear and use a wiggle test, because a cocked plunger can give a false good reading. [5] If the bores pass, check both valve body halves for warp; the fix is flat-sanding or gaskets. [5]

Read the Line Pressure Before Replacing Anything

Almost every 68RFE shift complaint touches line pressure, and the scan data tells you fast whether the hydraulics are healthy. GEARS gives the benchmarks: a stock truck idling in gear should show about 60 to 70 psi on both Commanded Pressure and Actual Pressure, with Line Pressure Duty Cycle at 22 to 24 percent. [5] A duty cycle of 18 percent or higher at idle shows healthy control. Anything under 10 percent is not acceptable, and a steady 5 percent means the system is at its limit and actual pressure is likely below what is commanded. [5]

GEARS' diagnostic order is worth following as written: review the repair and modification history, test drive while graphing scan data, compare commanded and actual pressure and duty cycle at idle, check duty cycle at a steady flat-highway cruise, and determine whether the truck is tuned. [5] A tune that commands more pressure than the pump can make will look exactly like a worn pressure regulator on the scan tool, and it will kill a warranty repair.

The 2019-2020 Valve Body Recall

Any 2019 or 2020 3500 with a 68RFE needs its recall status checked before a valve body is condemned. Safety recall W03 (NHTSA 20V-043) covers about 85,000 2019-2020 Ram 2500 and 3500 pickups with the 68RFE. FCA's dealer instructions describe "a buildup of pressure and heat inside the transmission" that can expel fluid from the dipstick tube. [3] The remedy replaces the lower valve body separator plate with kit CSKLW031AB (separator plate, check ball and fastener) and checks the PCM for current software. [3]

The recall procedure also gives you real assembly numbers for the lower valve body on these trucks: the guide pins torque to 6.5 N·m (57.5 in-lb), the valve body fasteners to 7.3 N·m (64.6 in-lb), and the 15 pan bolts to 9 N·m (80 in-lb) in a crisscross. Refill is about 5 quarts of ATF+4 (MS-9602-F), and the level is set with fluid at least 160°F, which FCA notes can take up to 20 minutes of idle in Park. [3] A truck that missed W03 is running the original plate, so any shift calibration or learn you do on it is built on the wrong hydraulics.

2024 Trucks: Hard Shifts and Limp Mode From a Cracked Thrust Plate

If the truck is a 2024 3500 or 2500 with the standard-output Cummins and the 68RFE (sales code DG7), check FCA TSB 21-054-24 (October 26, 2024, also released as RSU 24-149) before you chase shift quality. The bulletin covers a cracking rear selective thrust plate between the Number 6 thrust bearing and the reaction sun gear. To qualify, the truck must have the MIL on with one or more of these codes: P0218 (high temperature operation activated), P0716, P0729 and P0731 through P0735 (incorrect gear ratio), P0841, P0868 (fluid pressure low), P0871, P0876 and P0944 (loss of hydraulic pump prime). The customer complaint is hard shifting into gear, limp home mode, or both.

The repair is not a flash or a valve body. It is a 4.0 hour job: the converter comes out and the thrust plate gets replaced with one of five selective thicknesses (2.78, 2.86, 3.08, 3.23 or 3.38 mm), chosen from the VIN list. The parts list calls for 18 quarts of ATF+4 (68218057AC). If a 2024 truck shows a ratio code cluster like that, read the VIN against the bulletin before you replace any solenoid pack. A fresh fluid service will not fix it either; see our 68RFE Ram 3500 Cummins fluid change guide for what a service can and cannot do.

Repair Order That Works on a One-Ton

1. Confirm DG7. If it is an Aisin, stop and use Aisin information. [1]
2. Check recalls and bulletins by VIN. W03 on 2019-2020, 18-066-23 on 2019, 18-005-23 on 2022. [2][3]
3. Fluid level and condition. ATF+4, level set hot. A low unit flares; a burned one has already told you the pack is done.
4. Graph line pressure and duty cycle at idle and steady cruise against the GEARS numbers. [5]
5. Ratio math through each shift to separate clutch timing from converter slip. [1][5]
6. Valve body: vacuum test the SSV and TCC regulator bores, check for warp, test the OD dribbler with air. [5][6]
7. Quicklearn after any flash, valve body or hard-part repair, every time. [2][6]
8. FCA US LLC — Technical Service Bulletin 21-054-24 / RSU 24-149, Rear Selective Thrust Washer Failure (October 26, 2024). Backs the 2024 Ram 2500/3500 6.7L 68RFE (DG7) scope, the required DTC list, hard shift and limp home symptoms, the cracked rear selective thrust plate cause, the five selective thicknesses, the 4.0 hour labor time and 18 quarts of ATF+4 68218057AC. static.nhtsa.gov (PDF)

A solenoid pack is the right call when a solenoid or pressure switch code points at it and the circuit checks good to the connector. It is the wrong call for a worn SSV bore: a new solenoid pack bolted to a leaking valve body shifts the same way on the drive home. For capacities and the fill procedure, see the 68RFE fluid type and capacity guide and our transmission fluid spec chart.

FAQ

Why does my Ram 3500 Cummins 68RFE clunk on downshifts with the exhaust brake on?

FCA TSB 18-066-23 lists harsh downshift clunk during exhaust brake deceleration on 2019 Ram 2500 and 3500 Cummins trucks. The fix is a PCM flash followed by a 68RFE Quicklearn. If the clunk remains after the update, check line pressure and the solenoid switch valve bore.

Is there a TSB for 68RFE upshift flare on a Ram 3500?

Yes. TSB 18-005-23 (RSU 23-007) covers all 2022 Ram 2500 and 3500 Cummins pickups and, for 68RFE trucks, reduces audible engine flare during upshifts, helps prevent premature OD clutch wear and addresses 1-2-1 hunting on grades. For 2019 trucks, TSB 18-066-23 adds 68RFE upshift quality enhancements. Both require a Quicklearn after the flash.

What causes a 68RFE to start in second gear or bind up on shifts?

GEARS Magazine ties second-gear starts, binding on shifts, burned OD clutches and P0871 to a worn solenoid switch valve bore, and notes valve body warpage causes the same symptoms. Vacuum test the switch valve and plug, then check both valve body halves for warp before replacing parts.

What should 68RFE line pressure be at idle?

Per GEARS Magazine, a stock 68RFE idling in gear should show about 60 to 70 psi commanded and actual, with line pressure duty cycle at 22 to 24 percent. Eighteen percent or more is healthy, under 10 percent is not acceptable, and a steady 5 percent means the system is at its limit.

Sources