Allison code d5644

March 09, 2024, 10:21:16 am

OK, so on way home from Texas Custom Coach after some work on 6 packs. Went into limp mode in gear 3. No way out of it. Made it home and called for help. with engine still on. Since was not parked in our spot didn't want to not be able to restart engine in middle of parking lot. Told to shut down engine and restart. OK, now able to shift normally so put coach into slot. This AM pulled code from transmission.. d5644. Does not show up in any of my literature. Anyone had this code before and what does it forbode for our trip to FMCA in Tucson next week?

Jerre

Re: Allison code d5644

Reply #1 – March 09, 2024, 10:34:51 am

https://cdn.mpparts.com/pdfs/Trans%20Codes.pdf

If you miss a digit after D (such as 1, first code stored)

56 44 corresponds to

DIAGNOSTIC TRANSMISSION MAIN CODES 54–63 Diagnostic Transmission Codes

56 00 LOW RANGE VERIFICATION TEST

44 4TH RANGE VERIFICATION TEST

Something amiss with 4th gear range

Re: Allison code d5644

Reply #2 – March 09, 2024, 10:45:39 am

More info here CODE 56 XX RANGE VERIFICATION RATIO TEST (BETWEEN SHIFTS) - TM-9-2320-302-20_997

Note the added red - first things to check are batteries, connections to power/ground, and voltages

W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L

Main code 56 indicates a failed range verification speed sensor ratio test. The ratio test occurs after a shift and determines if a clutch has lost torque carrying capability. If output speed is above programmed output speed for a range but the correct speed sensor ratio is not present, the DO NOT SHIFT response is commanded and a range which can carry the torque without damage is commanded or attempted. Turbine and output speed sensor readings are used to calculate the actual ratio that is compared to the commanded ratio. Main code 56 can also be caused by the ECU being calibrated for a close ratio transmission and installed with a wide ratio transmission, or vice versa.

A. Active Indicator Clearing Procedure:

• Power down

• Manual — subcodes 11, 44, 66, 77 only

NOTE: When a code 22 16 (output speed fault) is also present, follow the troubleshooting sequence for code 22 16 first. After completing the 22 16 sequence, drive the vehicle to see if a code 56 XX recurs.

NOTE: Before troubleshooting, read Paragraph 5–6. Also, check battery and ECU input voltages.

NOTE: Intermittent connections or lack of battery-direct power and ground connections may cause this and other codes.

B. Troubleshooting:

1. After the transmission is at operating temperature, allow vehicle engine to idle on level ground for 3–4 minutes. Check the transmission fluid level. If improper fluid level is found, correct as necessary. Improper fluid level could be the cause of the code. Not enough or too much fluid may produce inadequate clutch pressure.

2. Connect a pressure gauge and check main pressure. If the pressure is not adequate, the pump is probably worn. See Appendix B for main pressure specifications.

3. If main pressure is adequate, check clutch pressure for the range indicated by following the procedure in Appendix B. The transmission range indicated by the trouble code can be found by referring to the solenoid and clutch chart in Appendix C. Drive the vehicle or use the diagnostic tool's clutch test mode and check clutch pressure.

4. If a clutch is leaking pressure, drain the fluid, remove the control module and check for damaged control module gaskets and stuck or sticking valves. Also look for damaged or missing face seals. If no problems are found, replace the solenoids for the clutches used in the range indicated by the code.

5. If replacing solenoids does not correct the pressure problem, a worn clutch or worn piston seals are probably the source of the pressure leak. Remove the transmission and repair or replace as necessary.

6. This code requires accurate output and turbine speed readings. If there were no transmission problems detected, use the diagnostic tool and check the speed sensor signals for noise (erratic signals) from low speed to high speed in the range indicated by the code.

7. If a noisy sensor is found, check the resistance of the sensor (300 ± 30 Ohms, refer to the code 22XX temperature variation chart) and its wiring for opens, shorts, and shorts-to-ground (refer to code 22XX). Carefully check the terminals in the connectors for corrosion, contamination, or damage. Ensure the wiring to the sensors is a properly twisted wire pair. Replace a speed sensor if its resistance is incorrect. Isolate and repair any wiring problems. [removed possible vehicle-specific note on sensor. Transmission data plate info should be used to get the correct part for a Foretravel]

8. If no apparent cause for the code can be found, replace the turbine and output speed sensors.

9. If the condition persists, replace the ECU. If replacing the ECU corrects the problem, reinstall the original (bad) ECU to confirm that the problem is in the ECU. If the original ECU now works, inspect the ECU connectors for any corrosion or damage which may cause an intermittent condition. If the original problem recurs, reinstall the replacement ECU.

Re: Allison code d5644

Reply #3 – March 09, 2024, 11:25:02 am

Thanks Michelle

Here is the link for the whole manual if you get bored some weekend. 500+ pages

https://trucktransdiag.com/downloads/wtec3.pdf

Now just need to see if it is a persistant problem.

Jerre

Re: Allison code d5644

Reply #4 – March 09, 2024, 01:12:38 pm

Jerre,

Several forum members have replaced the Allison output speed sensor, including us. It's not a big job, but you do need the info off the transmission data plate to order the correct one for the 4000-series retarder-equipped 2003 transmission. We bought ours through a Freightliner shop in either Vermont or New Hampshire 10 or more years ago.

You might check that sensor to see if its connector got bumped during the six-pack service.

FYI - not the same code, but definitely the 4th gear limp situation (found while searching for Allison output speed sensor, note the parts are for a 3000-series so don't use those part numbers) : Stuck in 4th gear

ETA - topic from 10 months ago with p/n and approximate co$t of sensor output speed sensor, allison

Re: Allison code d5644

Reply #5 – March 09, 2024, 05:04:16 pm

Quote from: DaBus – March 09, 2024, 11:25:02 am

Thanks Michelle

Here is the link for the whole manual if you get bored some weekend. 500+ pages

Now in the Forum Media section https://www.foreforums.com/index.php?media/item/allison-wtec3-3000-and-4000-series-electronic-cont.5073/

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