TRANSMISSION RANGE (TR) SWITCH
Note. TR switch may also be known as Park/Neutral Position (PNP) switch.
For PNP switch adjustment, see appropriate AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION SERVICING.
SHIFT LINKAGE
For shift linkage adjustment, see appropriate AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION SERVICING.
THROTTLE CABLE
For throttle cable adjustment, see appropriate AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION SERVICING.
PRELIMINARY CHECKS
Ensure engine is at normal operating temperature. Ensure fluid level is correct. Inspect and adjust throttle cable and shift linkage (if necessary). Ensure electronic component harness connectors are properly connected. Check idle speed RPM and adjust if necessary.
No Movement In Any Gear Position
Low fluid level, worn or seized oil pump, sticking regulator valve, clogged oil filter, broken planetary gear set, worn oil pump bushing, faulty torque converter or manual valve.
Lock-Up Does Not Occur
TCC control valve or clutch solenoid sticking. Faulty torque converter.
Poor 1st Gear Performance Or Slipping In "D" Or "2"
Forward clutch leaking due to OD case sealing ring failure. OD clutch slipping. Defective 1-2 shift valve.
Slipping In "L"
Forward clutch leaking due to OD case sealing ring failure. Low and reverse brake slipping or faulty low and reverse brake piston "O" ring.
Slipping In "R"
Direct clutch leaking due to center support sealing ring failure. Worn direct clutch.
Poor Or Slipping 1-2 Shift
Overdrive clutch leaking due to OD case sealing ring failure. Sticking regulator valve, faulty second brake, broken second brake piston or "O" ring, 1-2 shift valve sticking, shift solenoid No. 2 sticking, defective 2nd coast brake or sticking coast modulator valve.
Poor Or Slipping 2-3 Shift
Overdrive clutch leaking due to OD case sealing ring failure, worn direct clutch bushing, faulty direct clutch, 2-3 shift valve sticking, shift solenoid No. 1 sticking or clogged direct clutch piston check ball.
Poor Acceleration Or Surging In "D"
Stuck regulator valve, forward clutch leaking due to OD case sealing ring failure or faulty forward clutch.
Poor Or Slipping 3-4 Shift
Defective OD brake and/or clutch. 3-4 shift valve or shift solenoid No. 2 sticking.
Excessive Shock On 1-2 Shift
Sticking regulator valve, defective one-way clutch, faulty accumulator or 2nd brake piston.
Excessive Shock On 2-3 Shift
Sticking regulator valve, defective accumulator or direct clutch piston.
Excessive Shock On 3-4 Shift
Sticking regulator valve.
- Before testing transmission, ensure fluid level is correct and selector lever, throttle cable and idle speed are adjusted correctly. Battery must be fully charged for accurate testing.
- To aid in transmission fault diagnosis, determine if fault is hydraulic, electronic or a combination of both. Electronic control transmissions are capable of storing self-diagnostic codes. To determine if a fault is electrical, retrieve any stored diagnostic trouble codes. See MAZDA MIATA SB4A-EL ELECTRONIC CONTROLS article for electronic diagnosis.
HYDRAULIC PRESSURE TESTS
Note. Hydraulic pressure tests should be performed with transmission fluid temperature at normal operating temperature of 158-176°F (70-80°C).