Garage411 : ATOverhaul1FD3S

Mazda RX-7 Automatic Transmission Overhaul Part 1: road test results, stall speed and more

Mazda RX7 1993-1995 FD3S

RA4A-EL, RA4AX-EL and RB4A-EL


Mazda RX-7 RA4A-EL, RA4AX-EL and RB4A-EL Overhaul



APPLICATION AND LABOR TIMES



CAUTION: Disconnecting battery on models equipped with anti-theft radio require canceling of anti-theft operation. Refer to vehicle owner's manual to identify radio type.

IDENTIFICATION


Transmission model number is identified by a stamped metal plate attached to left or right side of rear transmission housing. See Fig. 1.

Fig. 1: Locating Transmission Identification Number (929 Shown, MPV and RX7 Similar)
Fig.1

DESCRIPTION AND OPERATION


The RA4A-EL, RA4AX-EL and RB4A-EL are 4-speed electronically controlled automatic transmissions that incorporate 5 multi-disc hydraulic clutches, 2 one-way clutches (sprag type) and a friction lined brake band that prevents rotation of rear sun gear drum. See Fig. 2 .

ON/OFF and duty cycle solenoids control shift changes, line pressure and torque converter lock-up. Solenoids are attached to valve body. Solenoids are operated by Transmission Control Module (PCM).

TCM receives information from various input devices and uses this information to control solenoids for transmission shifting, line pressure, shift feel and torque converter clutch lock-up.

Fig. 2: Cut-Away View (RA4A-EL Shown, RA4AX-EL and RB4A-EL Similar)
Fig.2

TROUBLE SHOOTING


INTRODUCTION

Preliminary Checks
Automatic transmission malfunction can be caused by either engine or transmission problems. Isolate malfunction to engine or transmission before proceeding with trouble shooting. Prior to trouble shooting check and adjust shift linkage, range switch and idle speed as needed. Ensure fluid level is correct. Check tires for correct inflation.

SYMPTOM DIAGNOSIS

Vehicle Does Not Move In Forward Or Reverse
internal transmission slippage, faulty valve body, faulty pressure control solenoid, faulty dropping resistor and/or worn parking mechanism.

Vehicle Moves In "N" Position
Possible causes: selector lever adjustment, faulty or misadjusted TP sensor, internal transmission slippage, faulty manual valve, faulty pressure control solenoid and/or faulty dropping resistor.

Excessive Vehicle Movement At Idle
Possible causes: high idle speed and/or high line pressure.

Low Maximum Speed and Poor Acceleration
Possible causes: low ATF level, selector lever adjustment, faulty or misadjusted TP sensor, low line pressure, internal transmission slippage, faulty valve body, faulty pressure control solenoid, faulty dropping resistor, worn shift solenoids "A" and/or "B", misadjusted transmission range switch, faulty HOLD switch, faulty output speed sensor, worn torque converter and/or low engine output.

No Shifting
Possible causes: worn shift solenoids "A" and or "B", misadjusted transmission range switch, faulty HOLD switch, faulty output speed sensor, faulty valve body, poor ground and/or faulty TCM.

Transmission Does Not Shift To 4th Gear
Possible causes: faulty TFT sensor, worn shift solenoids "A" and/or "B", worn overrunning clutch solenoid, faulty valve body, misadjusted transmission range switch, faulty output speed sensor, faulty 4th gear inhibit signal, shorted DLC connector TAT terminal, faulty HOLD switch, poor ground and/or faulty TCM.

Abnormal Shift
Possible causes: low ATF level, poor ground, misadjusted TP sensor, faulty output speed sensor, faulty TCM and/or faulty valve body.

Frequent Shifting
Possible causes: misadjusted TP sensor, poor ground and/or faulty TCM.

Shift Point High Or Low
Possible causes: misadjusted TP sensor, faulty engine RPM signal, faulty output speed sensor and/or faulty AC signal.

Torque Converter Clutch (TCC) Non-Operation
Possible causes: worn TCC solenoid, worn TCC control solenoid, faulty valve body, faulty TFT sensor,misadjusted TP sensor, faulty closed throttle position switch, faulty engine RPM signal, faulty output speed sensor and/or faulty transmission range sensor.

No Kickdown
Possible causes: faulty or misadjusted TP sensor, faulty valve body, faulty HOLD switch and/or faulty output speed sensor.

Transmission Shift Flare Under Acceleration
Possible causes: low ATF level, selector lever adjustment, faulty or misadjusted TP sensor, low line pressure, internal transmission slippage, faulty valve body, faulty pressure control solenoid and/or faulty dropping resistor.

Transmission Shift Flare Or Slipping Shift During Upshifts Or Downshifts
Possible causes: low ATF level, selector lever adjustment, faulty or misadjusted TP sensor, low line pressure, internal transmission slippage, faulty valve body, faulty pressure control solenoid, faulty dropping resistor, faulty input/turbine speed sensor, faulty output speed sensor and/or faulty MAP sensor.

Harsh (Shudder) TCC Engagement
Possible causes: misadjusted ignition timing, low ATF level, worn TCC solenoid, worn TCC control solenoid, faulty valve body, misadjusted TP sensor, faulty closed throttle position switch, faulty engine RPM signal, faulty output speed sensor, low line pressure, faulty dropping resistor and/or faulty pressure control solenoid.

Excessive "N" To "D" Or "N" To "R" Shift Shock
Possible causes: low ATF lever, high idle speed, faulty TP sensor, high line pressure, faulty valve body, internal clutch slippage, worn pressure control solenoid, faulty dropping resistor, worn N-D or 3-4/N-R accumulator, faulty or misadjusted transmission range switch and/or faulty input/turbine speed sensor.

Excessive Shift Shock During Upshifts Or Downshifts
Possible causes: low ATF lever, faulty TP sensor, high line pressure, faulty valve body, internal clutch slippage, worn pressure control solenoid, faulty dropping resistor, faulty closed throttle position switch, faulty TFT sensor, faulty input/turbine speed sensor, faulty output speed sensor and/or faulty MAP sensor.

No Engine Braking
Possible causes: low ATF lever, internal clutch slippage, faulty valve body, worn overrunning clutch, faulty or misadjusted TP sensor, faulty 4th gear inhibit signal and/or faulty or misadjusted transmission range switch.

Transaxle Overheats
Possible causes: low ATF level, internal component failure, faulty pressure control solenoid, faulty or misadjusted TP sensor, faulty dropping resistor, worn TCC solenoid, worn TCC control solenoid and/or fluid cooling system.

Engine Stalls When Shifted Into Forward Or Reverse Gears
Possible causes: low idle speed, faulty valve body, faulty PNP switch signal, faulty or misadjusted transmission range switch, faulty input/turbine speed sensor and/or faulty output speed sensor.



CLUTCH AND BAND APPLICATION TABLES

Fig. 3: Clutch and Band Application Table (HOLD Type Systems)
Fig.3
Fig. 4: Clutch and Band Application Table (HOLD Type Systems With Power/Economy Switch)
Fig.4
Fig. 5: Clutch and Band Application Table (O/D OFF Type Systems)
Fig.5

TESTING
Before testing transmission, ensure fluid level is correct and shift linkage, range switch and idle speed are adjusted correctly.

TIME LAG
With engine at idle, shift selector from "N" to "D", "N" to "D" HOLD or O/D OFF (as equipped) and "N" to "R". Time lag for transmission to engage should be less than one second for "N" to "D" and less than 1.2 seconds for "N" to "R".

TIME LAG RESULTS

Longer Than Specified In "N" To "D" & "N" To "D" HOLD Or O/D OFF

Low line pressure. Forward clutch slipping.

Forward one-way clutch slipping. Longer Than Specified In "N" To "D"

Low line pressure. Low one-way clutch slipping. N-D accumulator not operating properly.

Longer Than Specified In "N" To "D" HOLD

Low line pressure. Brake band slipping. 1-2 accumulator not operating properly.

Longer Than Specified In "N" To "R"

Low line pressure. Reverse clutch slipping. Low and reverse brake slipping. 3-4/N-R accumulator not operating properly.


ROAD TEST


INTRODUCTION

Preparation
Check all fluid levels and correct if necessary. Warm engine and transmission to operating temperature. If any problems occur during road test. Test Procedure
1. Check for shift point, shift pattern and shift shock. Shift selector to "D" range (MPV (1995 4WD and 1996 All), RX7 and 929), "D" range ECONOMY mode (1995 MPV 2WD). Accelerate vehicle at half and full throttle, ensure 1-2, 2-3 and 3-OD upshifts, downshifts and lock-up are obtained. Note speed and compare with appropriate SHIFT SPEED CHART. See Fig. 6 -Fig. 10 . Note upshifts for shift shock and slippage.
2. On 1995 MPV 2WD, select POWER mode. Note shift points, and any shock and slippage.
3. On all models, when driving in OD, shift to "S" and check that OD-3 downshift occurs immediately.
4. Select HOLD mode. Check for 2-3 upshifts and downshifts. Check for lock-up and no 1st or "OD".
5. Decelerate vehicle. Check for engine braking in 3rd and 2nd gears when throttle is open 1/8 or less.
6. Drive in 3rd and 4th gear to ensure no unusual noise or vibration is heard. Check torque converter, driveshaft(s) and differential for source of unusual noise. Ensure kickdown operates properly and shift points match appropriate SHIFT SPEED CHART.

POWER or NORMAL driving mode is automatically selected according to throttle opening. O/D does not operate when ATF temperature is below 50°F (10°C) or when cruise control is operating with a 5 MPH difference between preset cruise speed and vehicle speed. TCC lock-up does not operate when throttle is closed with vehicle below 74 MPH or when ATF is below 104°F (40°C).

Fig. 6: 1995 MPV 2WD Shift Speed Chart
Fig.6
Fig. 7: 1995 MPV 4WD Shift Speed Chart
Fig.7
Fig. 8: 1995-96 MPV Shift Speed Chart
Fig.8
Fig. 9: RX7 Shift Speed Chart
Fig.9
Fig. 10: 929 Shift Speed Chart
Fig.10
ROAD TEST RESULTS

Starts In "S" Or Shifts Directly From "L" To "OD"

Stuck shift solenoid "A". Stuck shift valve "A".

Starts In "OD"

Stuck shift valve "B". Stuck shift solenoid "B".

No Shift

Stuck shift solenoid "A" and/or "B", or stuck shift valve "A" and/or "B".

Incorrect Shift Points
TP sensor out of adjustment. Output speed sensor not operating properly.

Shift Shock Or Slipping Is Felt
Stuck line pressure solenoid. Accumulators not operating properly. TP sensor out of adjustment. Output speed sensor not operating properly. TFT sensor not operating properly. Worn clutches, one-way clutches and/or brakes.

No Engine Braking
Stuck overrunning clutch solenoid. Worn clutches and/or brakes.

No Lock-Up Shift
Stuck lock-up solenoid. Stuck lock-up control valve.

STALL SPEED

CAUTION: Stall and line pressure tests generate high engine and transmission temperatures. DO NOT hold throttle open more than 5 seconds. Allow engine to idle in "P" or "N" for at least one minute between tests.

Preparation
Check all fluid levels and correct if necessary. Warm engine and transmission to operating temperature. Prior to performing stall test, block front and rear wheels and set parking brake.
Connect tachometer to engine. Ensure engine idle speed and ignition timing is correct.


Apply foot brake firmly and shift selector to "D" range. Press accelerator pedal to floor and note maximum RPM. Select "S", "R" and "L" ranges and repeat.

STALL SPEED SPECIFICATIONS

STALL SPEED RESULTS

Above Specification In All Ranges
Insufficient line pressure, worn oil pump. Oil leakage from oil pump, control valve and/or transmission case. Stuck pressure regulator.

Above Specification In "D" and "S"
Forward clutch slipping. Forward one-way clutch slipping. Low one-way clutch slipping.

Above Specification In "R" Range
Low and reverse brake slipping. Reverse clutch slipping. Perform road test to see if low and/or reverse brake or reverse clutch is at fault. Results indicate the following:

Below Specification In All Ranges
Low engine output. One-way clutch in torque converter slipping.

LINE PRESSURE TEST
1. Connect gauges to appropriate line pressure inspection ports. See Fig. 11. Connect tachometer to engine. Ensure engine idle speed and ignition timing is correct.


Apply foot brake firmly and shift selector to "D" range.
2) Press accelerator pedal to floor and note pressure gauge. Release throttle to read pressure at idle. Select "S", "R" and "L" ranges and repeat.

Fig. 11: Identifying Transmission Fluid Passages
Fig.11
LINE PRESSURE SPECIFICATIONS

Low Pressure At Idle (All Ranges)
Worn oil pump. Damaged control piston in oil pump. Pressure regulator valve or plug sticking. Damaged pressure regulator valve spring. Fluid leakage between oil strainer and pressure regulator valve.

Low At Idle In "D", "S" Or "L"
Fluid leakage from hydraulic circuit of forward clutch.

Low At Idle In "D" and "S" HOLD Mode
Fluid leakage from hydraulic circuit of band servo 2nd apply side.

Low At Idle In "R"
Fluid leakage from hydraulic circuit of reverse clutch.

Low At Idle In "R" and "L"
Fluid leakage from hydraulic circuit of low and reverse brake.

High At Idle
Throttle sensor out of adjustment. Damaged thermosensor. Line pressure solenoid sticking. Short circuit of line pressure solenoid circuit. Pressure modifier valve sticking. Pressure regulator valve or plug sticking.

Mazda RX-7 RA4A-EL, RA4AX-EL and RB4A-EL Overhaul
Low At Stall Speed Throttle sensor out of adjustment. Damaged control piston in oil pump. Line pressure solenoid sticking. Short circuit of line pressure solenoid circuit. Pressure regulator valve or plug sticking. Pressure modifier valve sticking. Pilot valve sticking.



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Mazda RX7 1993-1995 FD3S

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