Diagnosis & Overhaul - Awd Ford Tempo I

DESCRIPTION

All-Wheel Drive (AWD) transfer case used in the Tempo is a part time unit activated by a dash switch. The AWD switch actuates a vacuum servo system, located on transfer case. Vacuum is routed to vacuum servo by dual electronic-activated solenoids, located on right front shock tower. (Scheme 3)

Scheme 1

1. Ensure transaxle is in Park. Loosen 2 rear engine mount bolts. DO NOT remove bolts. Using a screwdriver and soft hammer, remove cup plug, and drain fluid. Install Measuring Gauge (T87P-4020-B) through cup plug opening and position into input gear.
2. Tighten wing nut on measuring gauge. Remove bolt and install a dial indicator. Rotate both front wheels together until park gear is wedged tightly against parking pawl. While maintaining load on park gear and parking pawl, position dial indicator against measuring gauge. (Scheme 1)(Scheme 1): Checking Backlash
3. Push downward on measuring gauge, while still maintaining load, to check backlash. Ensure backlash is.012-.024" (.30-.61 mm) on approximately a 3" portion of ring gear. If backlash is as specified, remove equipment and install cup plug. Fill transfer case. If backlash is not as specified, see «SETTING BACKLASH»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd__setting-backlash) under OVERHAUL.

VACUUM DIAGNOSIS

1. Test system for leaks. Take vacuum gauge reading from rubber "T" at input to dual solenoids with engine running and AWD switch in ON position, if vacuum reading is less than 16-20 in. Hg (54-67 kPa) there is a leak in vacuum lines to reservoir or the reservoir leaks. Inspect lines and test reservoir with hand pump. Repair as necessary. If vacuum is sufficient go to next step.
2. Check for vacuum at output side of dual solenoids as described in previous step, one solenoid at a time. Test 4-wheel drive solenoid with AWD switch in ON position and 2-wheel drive solenoid with AWD switch in OFF position. If vacuum is less than 16-20 in. Hg (54-67 kPa), see «ELECTRICAL DIAGNOSIS»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd__electrical-diagnosis) and test solenoids. If vacuum is sufficient, go to next step.
3. Take vacuum gauge reading from single to double connector at vacuum servo. Test at vacuum "T" entering "A" side of vacuum servo with engine running and AWD switch to ON position. (Scheme 6) Test "B" side with AWD switch in OFF position. If vacuum is less than 16-20 in. Hg (54-67 kPa) repair vacuum source between dual solenoids and vacuum servo. If vacuum is sufficient go to next step.
4. Raise vehicle on hoist with transaxle in "N" position. Using hand held vacuum pump, apply 16-20 in. Hg (54-67 kPa) vacuum to Red tube connector of vacuum servo and block off Black tube. Rotate front wheels by hand; if rear wheels do not rotate, replace vacuum servo.

ELECTRICAL DIAGNOSIS

Note. For circuit and terminal identification during ELECTRICAL DIAGNOSIS (Scheme 7)

AWD Relay Test

1. With ignition off, using test light attached to battery voltage, backprobe terminals No. 1 and 5 of AWD relay No. 1. Relay is located above blower motor, under right side of dash. Test light should light. It light does not come on, repair open in Black ground circuit wire. With ignition on and AWD switch in ON position, touch test light attached to battery voltage to terminal No. 3 of AWD relay No. 1. Test light should light. If light does not come on, go to next step. Without moving test light, turn AWD switch off and light should go out. If light goes out, proceed to step 3). If light does not go out, replace AWD relay No. 1.
2. If test light does not light at terminal No. 3, ensure ignition is on and AWD switch is in ON position. Test for battery voltage at terminal No. 2. If battery voltage is not present, replace AWD relay No. 1 and proceed to next step. If there is battery voltage at terminal No. 2, test for short to voltage in Brown wire between AWD relay No. 1 and AWD switch. If no short is located, backprobe Brown wire terminal at AWD switch with switch in ON position. If voltage is present, replace AWD switch and proceed to next step.
3. With ignition on and AWD switch in OFF position, test for battery voltage at terminal No. 5 at AWD relay No. 2. Relay is located to right of blower motor, under right side of dash. If voltage is present, without moving test light, turn AWD switch to ON position. Light should go out. If light goes out, proceed to AWD SOLENOID TEST. If light does not go out, test for battery voltage at terminal No. 2 of AWD relay No. 2. Test light should light. If light does not come on, go to next step. If test light does light at terminal No. 2, turn ignition off. Using a test light attached to battery voltage, backprobe terminal No. 1 at AWD relay No. 2. Test light should light. If light comes on, replace AWD relay No. 2. If light does not come on, repair open in Black/Yellow ground circuit wire.
4. If test light does not light at terminal No. 2 of AWD relay No. 2, backprobe Yellow wire terminal at AWD switch with switch in ON position. If battery voltage is present, repair open in Yellow wire between AWD switch and AWD relay No. 2. If battery voltage is not present, backprobe Gray/Yellow wire terminal at AWD switch with ignition switch in ON position. If battery voltage is not present, repair power supply to AWD switch. If voltage is present at Gray/Yellow wire terminal, replace AWD switch.

AWD Solenoid Test

1. With ignition on and AWD switch in OFF position, ensure air can be blown through 2-wheel drive solenoid. If air passes through solenoid, proceed to next step. If air does not pass through solenoid. backprobe Orange wire terminal of 2-wheel drive solenoid for battery voltage. If battery voltage is present, turn ignition off. Using test light attached to battery voltage, backprobe Black wire terminal of 2-wheel drive solenoid. Test light should light. If light comes on, replace 2-wheel drive solenoid. If test light does not light at Black wire terminal of 2-wheel drive solenoid, repair open Black wire to ground. It battery voltage is not present at Orange wire terminal of 2-wheel drive solenoid, repair open in Orange wire from terminal No. 5 of AWD relay No. 2.
2. With ignition on and AWD switch in ON position, ensure air can be blown through 4-wheel drive solenoid. If air passes through solenoid, testing is complete. If air does not pass through solenoid, backprobe Purple wire terminal of 4-wheel drive solenoid for battery voltage. If battery voltage is present, turn ignition off. Using test light attached to battery voltage backprobe Black wire terminal Of 4-wheel drive solenoid. Test light should light. If light comes on, replace 4-wheel drive solenoid. If test light does not light at Black wire terminal of 4wheel drive solenoid, repair open Black wire to ground. If battery voltage is not present at Purple wire terminal of 4-wheel drive solenoid, repair open in Purple wire from terminal No. 4 of AWD relay No. 2.

Removal

1. Loosen 2 rear engine mount bolts to gain access to transfer case cup plug. DO NOT remove bolts. Using a screwdriver and hammer, remove cup plug to drain fluid from transfer case.
2. Remove vacuum line bracket. Disconnect drive shaft from transfer case yoke. Check backlash. See «CHECKING BACKLASH»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd) under ON-VEHICLE SERVICE. Remove vacuum servo shield.
3. Remove vacuum lines from vacuum servo, Place a jack under transfer case. Remove bolts securing transfer case to transaxle, noting location of each bolt. Remove transaxle.

Scheme 2

1. Check backlash. See «SETTING BACKLASH»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd__setting-backlash) under OVERHAUL. Install transfer case. Install bolts, in proper location, and tighten in sequence. (Scheme 2) (Scheme 2): Mounting Bolts Tightening Sequence
2. Install vacuum lines. Install shield. Install drive shaft to yoke. Loctite drive shaft retaining bolts and tighten to specification. Install vacuum line retaining bracket. Install cup plug. Fill transfer case.

Removal & Installation

Remove shield from vacuum servo. Disconnect vacuum lines. Remove transfer case from vehicle. Remove support bracket. Remove 3 snap rings from servo shift rod and discard. Remove vacuum servo from transfer case. (Scheme 3) To install, reverse removal procedure.

Identifying Vacuum Components. Scheme 3

Scheme 4

1. Remove transfer case. See «REMOVAL & INSTALLATION»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd__removal-installation). Remove transfer case side cover. Remove pinion gear housing assembly. (Scheme 4) Remove and discard "O" ring. Remove shim(s) and retain for reassembly purposes. Place pinion gear assembly in a soft-jawed vise. (Scheme 4): Exploded View of AWD Transfer Case
2. Remove yoke. Using a soft hammer, tap pinion gear shaft from housing. Remove collapsible spacer and discard. Install yoke nut to protect threads. Press bearing from shaft. Remove oil seal from housing. Remove bearing races from housing.
3. Remove snap rings from vacuum servo shaft and shift fork. Remove vacuum servo and discard "O" ring. Remove shift fork and clips. Remove input gear bearing cap. Rotate bearing. Remove 2-piece snap ring. Using a screwdriver, remove inner snap ring between input gear and bearing.
4. Slide bearing toward input gear, and remove outer snap ring. Remove cup plug. Slide input shaft assembly toward bearing, and remove assembly from transfer case. Remove assembly bearing from input shaft. Remove shift collar from clutch shaft. Remove nut and washer from clutch shaft.
5. Using a soft hammer, tap clutch shaft out of case. Discard collapsible spacer. Remove drive gear. shim(s) and bearing from housing. Retain shim(s) for reassembly purposes.
6. Press inner bearing from clutch shaft. Place clutch shaft in a soft-jawed vise. Remove clutch shaft pilot bearing. Using a slide hammer, remove bearing races from transfer case.

Scheme 5

1. Install clutch shaft bearing races. Install new clutch shaft pilot bearing, with tapered end toward clutch shaft. Press inner bearing onto clutch shaft.
2. Install new collapsible spacer on clutch shaft. Install clutch shaft in case. Install bearing, shim(s) and drive gear. Install washer and nut. Tighten nut until rotating torque is 4-8 INCH lbs. (.45-.91 N.m).
3. Install new bearing races in pinion gear housing. Install new oil seal and apply grease to lip of seal. Press new bearings onto pinion gear shaft. Install new collapsible spacer. Install pinion gear assembly into housing. Install yoke washer and nut. Tighten nut until rotating torque is 15-32 INCH lbs. (1.7-3.6 N.m). NOTE: When checking rotating torque, if specification is exceeded, new collapsible spacer must be installed.
4. Install new "O" ring on pinion gear housing. Position shim(s) on housing. Install pinion gear housing and tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS TABLE»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd). Position a dial indicator against pinion gear and check backlash. Ensure backlash is.004-.006" (.10-.15 mm). Adjust as necessary by changing shims.
5. Apply White marking compound on gear teeth and check contact pattern. If contact pattern is not within primary area of gear tooth surface, adjust shim thickness between pinion gear assembly and transfer case. Recheck backlash after adjustment.
6. Install shift collar and position bearing onto input shaft. Install input shaft assembly. Slide bearing toward input gear, and install outer snap ring. Slide bearing toward case, and install inner snap ring. Ensure snap rings are properly seated. Install 2-piece snap ring.
7. Install bearing cap and tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd) table. Install shift fork onto clutch collar. Install new "O" ring onto vacuum servo shaft and lubricate with ATF. Install vacuum servo. Install shift fork snap rings. (Scheme 5) Apply silicone sealant to side cover mating surface. Install side cover and tighten bolts to specification. (Scheme 5): Installing Vacuum Servo CAUTION: Excess silicone sealant can contaminate ATF, which can lead to transaxle failure.
8. Set transfer case backlash. See «SETTING BACKLASH»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd__setting-backlash) under OVERHAUL. After backlash check, install new "O" ring and cup plug. Install transfer case.

Installation

With transfer case removed from vehicle, position thickest Gasket (7A191-H) onto transfer case. Install transfer case and tighten the retaining bolts in sequence and to specification. (Scheme 2) Refer to the TORQUE SPECIFICATIONS table.

SETTING BACKLASH

1. Install Measuring Gauge (T87P-4020-B) through cup plug opening, against input gear. Tighten wing nut on measuring gauge.
2. Ensure transaxle is in Park. Remove bolt and install a dial indicator. (Scheme 1) Rotate both wheels until park gear is wedged tightly against parking pawl.
3. While maintaining load on park gear, push measuring gauge upward and zero dial indicator. Push downward on measuring gauge and check backlash. Ensure backlash is.012-.024" (.30-.61 mm) on approximately a 3" portion of ring gear. If backlash is as specified, remove equipment and install cup plug.
4. If backlash is not as specified, remove the transfer case and install proper gasket to obtain specified backlash. Refer to the «CASE GASKET SELECTION TABLE»(/ford/tempo/i-1983-1994/remont/transfer-case/#diagnosis-overhaul-awd). Install new gasket and recheck backlash.

CASE GASKET SELECTION

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Transfer Case Vacuum Diagram. Scheme 6

Transfer Case Wiring Diagram. Scheme 7

See also:
• SETTING BACKLASH
• ELECTRICAL DIAGNOSIS
• CHECKING BACKLASH
• REMOVAL & INSTALLATION