P0732-GEAR RATIO ERROR IN 2ND

For a complete wiring diagram Refer to Section 8W

Theory of Operation


The transmission system uses two speed sensors, one to measure input rpm and one to measure output rpm. These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through the following checks:

1) Once in a particular gear, if the gear ratio varies from the correct gear ratio, the corresponding in-gear trouble code is set (DTCs P0731-36 and P1736).

2) An excessive change in input or output speeds indicating signal intermittent may result in the DTCs P0716 and/or P0721 being set.

3) If the common speed sensor ground circuit is lost, both sensor inputs will read the pulses from the input speed sensor when at a stop in neutral. Since the input speed sensor reads 60 teeth from the input clutch hub and the output speed sensor reads 30 teeth from the park gear, the result is an apparent speed ratio of 1:2 and may cause the DTC P1794 to set.



Possible Causes
RELATED DTCS PRESENT
INPUT SPEED SENSOR OR WIRING
LOW FLUID LEVEL
CRACKED OR MIS-INSTALLED PRIMARY OIL FILTER OR SEAL
WORN SOLENOID SWITCH VALVE OR PLUGS
STUCK OR STICKING MAIN REGULATOR VALVE
BURNED UD OR 2C CLUTCH
CUT 2C OR UD PISTON SEAL
BROKEN 2C PISTON CASTING
BROKEN OR MISSING 2C BLEED ORIFICE
BROKEN OR MISSING UD BLEED ORIFICE
CUT 2C OR UD ACCUMULATOR PISTON SEAL
CRACKED 2C OR UD ACCUMULATOR PISTON
CUT OR MISSING #5 OR #7 CHECK BALL
TRANSMISSION SOLENOID/TRS ASSEMBLY
BROKEN WELD - REACTION CARRIER TO REVERSE SUN GEAR
MISSING TEETH ON INPUT CLUTCH HUB TONE WHEEL

Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)



Diagnostic Test

1. CHECK FOR RELATED DTCS

With the scan tool, check for other transmission DTCs.

Are there any Transmission solenoid, line pressure, speed sensor, and/or loss of prime DTCs present?

Yes


No

2. CHECK IF DTC IS CURRENT

With the scan tool, read and record the DTC EVENT DATA.

NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test procedure.



Does the DTC EVENT DATA display information for the DTC P0732?

Yes


No

3. CHECK DTC EVENT DATA

In the DTC EVENT DATA, identify the DTC that was recorded earlier.

Does the DTC EVENT DATA display information for the DTC P1790, with target gear = 2nd, or with both 2C and UD clutches applying?

Yes


No

4. CHECK RPM IN DTC EVENT DATA

Refer to the DTC EVENT DATA recorded earlier.

Does the Input rpm read zero?

Yes


No

5. CHECK LINE PRESSURE READING

Refer to the DTC EVENT DATA recorded earlier.

Is the line pressure reading more than 10 psi below the desired line pressure?

Yes


No

6. CHECK TRANSMISSION OIL FILTER

Turn the ignition off to the lock position.
Remove and inspect the Transmission Oil Pan for excessive debris per the Service Information.
Remove and inspect the Primary Oil Filter per the Service Information.

NOTE: Make sure the Primary Transmission Oil Filter and seal are properly installed and are not cracked or split.



Does the Oil Pan contain excessive debris and/or is the Primary Oil Filter cracked, plugged or mis-installed?

Yes


No

7. CHECK IF THE DTC P0732 IS CURRENT

With the scan tool, perform the 2nd Gear Clutch Test. Follow the instructions on the scan tool.
Increase the throttle angle, TPS Degree, to 30 degrees for no more than a few seconds.

CAUTION: Do not overheat the transmission.


NOTE: If the 2C clutch is faulty, the overrunning clutch will hold and the slip test will pass. The 2nd gear clutch test will not detect a faulty 2C clutch. However, it will detect a faulty UD clutch.



Did the clutch test pass, did the Input Speed remain at zero?

Yes


No

8. CHECK FOR INTERMITTENT OPERATION

Check the Shifter adjustment per the Service Information.
Intermittent gear ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed Sensor Ground circuit.
Check the Speed Sensor wiring and connectors for good connection, then perform a wiggle test using the Transmission Simulator, Miller tool #8333.

Were there any problems found?

Yes


No

9. CHECK FOR SLIPPAGE

With the scan tool, erase Transmission DTCs.
Road test the vehicle.

Is there an obvious slippage noticed in 2nd gear, or runaway on the 1–2 shift?

Yes


No

10. CHECK THE UD HYDRAULIC CLUTCH CIRCUIT

Remove Transmission Oil Pan and check for excessive debris.
Remove the Valve Body and air check the UD hydraulic clutch circuit (in the case) per the Service Information.

NOTE: The UD clutch passage contains a small bleed orifice, a small amount of air leakage is normal.



Were there any problems found, excessive debris and/or excessive air leakage in the UD clutch hydraulic circuit?

Yes


No

11. CHECK THE UD ACCUMULATOR PISTON

Check the UD bleed orifice, accumulator piston, and accumulator piston seal in the main valve body.

Were there any problems found?

Yes


No

12. CHECK FOR EXCESSIVE DEBRIS

Remove the Transmission Oil Pan and check for excessive debris.
If grey sludge is present, check for a improperly assembled 2C clutch with the thick reaction plate not against the case.
Remove the valve body and air check the 2C hydraulic clutch circuit (in the 2C/4C clutch retainer) per the Service Information.

NOTE: The 2C clutch passage contains a small bleed orifice, a small amount of air leakage is normal.



Were there any problems found, excessive debris, improperly assembled 2C clutch and/or excessive air leakage in the 2C hydraulic clutch circuit?

Yes


No

13. CHECK THE 2C ACCUMULATOR

Check the 2C Accumulator piston for cracks or a cut seal.
Check for a cut or missing #7 or #5 check ball.
Check the Solenoid Switch Valve and its plugs for sticking in its bore or excessive wear.

Were there any problems found

Yes


No

14. CHECK FOR BROKEN REVERSE SUN GEAR WELD

Working through the windows in the bottom of the case, check for a broken Reverse Sun gear weld to the reaction carrier as follows:
1) Hold the Transmission Output Shaft by holding the Transmission Manual Lever in the park position.
2) Rotate the Input Annulus gear and drive shell (the drum that encloses the two rearmost carriers).
3) Check to see if the reaction carrier (the front-most carrier, whose outer shell is splined to the 2C clutch) is rotating faster than the drive shell is being turned.

Is the reaction carrier turning faster than the drive shell?

Yes


No

15. CHECK IF DTC RESETS


Did the DTC P0732 reset during the road test?

Yes


No

16. LIST OF POSSIBLE CAUSES

If any other DTCs set during the road test, refer to the appropriate symptom in the Transmission category.
If no other DTCs set during the road test, below is a list of possible causes, but not strictly limited to those:

View repair

Repair

17. INTERMITTENT DTC

The conditions to set this DTC are not currently present.
With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.
Check the gearshift linkage adjustment.
Intermittent Gear Ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed Sensor Ground circuit.
Remove the Starter Relay.

CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.


WARNING: The Starter Relay must be removed from the PDC. Failure to do so can result in personal injury or death.


NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.


Install Transmission Simulator, Miller tool #8333.
Wiggle wiring and connectors while checking for intermittent operation with the Transmission Simulator.
Gear ratio DTCs can also be set under extreme temperature conditions.
Verify if the problem is only experienced under extreme hot or cold conditions.

Were there any problems found.

Yes


No