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TRANSMISSION SERVICING - A/T

1988 Jeep Cherokee

1988 Automatic Transmission Servicing JEEP

LUBRICATION

SERVICE INTERVALS

Transmission

Check fluid level and condition of fluid at each engine oil change. Under normal, light duty operating conditions, change fluid, replace filter and adjust bands every 2 yrs. or 25,000 miles. Under heavy duty service, change fluid, replace filter and adjust bands every 12 months or 12,500 miles.

Transfer Case

Check transfer case fluid every 12,000 miles and replace fluid every 30,000 miles.

CHECKING FLUID LEVEL

Transmission

Park vehicle on a level surface and apply parking brake. With engine idling at normal operating temperature, move transmission selector lever through all gears, ending in "N" ("P" for AW-4 transmission). Check fluid level. Fluid level should be between "FULL" and "ADD ONE PINT" mark on dipstick. Add fluid as needed. DO NOT overfill.

Transfer Case

Remove fill plug. Check oil level. If level is not up to fill plug opening, add lubricant until it is.

RECOMMENDED FLUID

Both transmissions and transfer cases use DEXRON-II ATF.

FLUID CAPACITY

NOTE: Transmission and converter capacities are approximate. Fluid level should always be determined by reading on dipstick, rather than amount of fluid added.

TRANSMISSION REFILL CAPACITIES

Application Quantity

All Models

Including Converter 8.5 qts . (8.0L)

Without Converter 4.3 qts. (4.0L)

TRANSFER CASE REFILL CAPACITIES

Application Capacity

Model 207 4.5 pts. (2.1L)

Model 208 6.0 pts. (2.8L)

Model 228 7.0 pts. (3.3L)

Model 229 6.0 pts. (3.8L)

DRAINING & REFILLING

Transmission

  1. Loosen oil pan bolts, tap pan to break it loose and allow
    fluid to drain. Remove pan. Install new filter on bottom of valve
    body and tighten retaining screws. Install new "O" ring on fluid
    pick-up pipe (if needed). Clean oil pan and install with new gasket.

  2. Refill transmission with fluid. Start engine and allow to
    run at curb idle for a few minutes. With vehicle on level surface,
    engine idling and parking brake applied, move shift selector lever
    through all gear ranges, ending in "N" ("P" for AW-4 transmission)
    .
    Add fluid up to "ADD ONE PINT" mark on dipstick.

  3. Recheck fluid level when transmission reaches normal
    operating temperature. Fluid should be between "ADD ONE PINT" and
    "FULL" marks on dipstick. Transmission must NOT be overfilled.

Transfer Case

Remove drain plug from transfer case. Remove fill plug for easier draining. With fluid fully drained, reinstall drain plug. Fill transfer case to fill plug opening with Dexron II.

ADJUSTMENT

NOTE: Bands on the AW-4 (4-speed overdrive) transmission are not adjustable. If slippage occurs, bands must be replaced.

KICKDOWN (FRONT) BAND

  1. Locate kickdown band adjusting screw on left side of case
    (near throttle lever shaft)
    . Loosen adjusting screw lock nut and back
    off approximately 5 turns. Ensure adjusting screw turns freely in
    case.

  2. Using Adapter (J-24063) and 5/16" square socket, tighten
    screw to
    36 INCH lbs. (4 N.m). If adapter is not used, tighten screw
    to 72 INCH lbs. (8 N.m). Back off adjusting screw. See KICKDOWN

(FRONT) BAND ADJUSTMENT table. Hold adjusting screw in position and tighten lock nut to 35 ft. lbs. (48 N.m).

KICKDOWN (FRONT) BAND ADJUSTMENT

Application (1) Back Off Screw

All Models 2 1/2 Turns

(1) - Tighten screw to 72 INCH lbs. (8 N.m) and back off indicated number of turns.

LOW-REVERSE (REAR) BAND

  1. Raise vehicle, drain transmission fluid and remove oil
    pan. Locate adjusting screw on rear servo lever. Loosen adjusting
    screw lock nut and back off about 5 turns.

  2. Tighten screw to 41 INCH lbs. (4.6 N.m) and back off
    screw at indicated number of turns. See LOW-REVERSE (REAR) BAND
    ADJUSTMENT table. Hold adjusting screw in position and tighten lock
    nut to
    35 ft. lbs. (48 N.m). Install oil pan and fill transmission

with fluid.

LOW-REVERSE (REAR) BAND ADJUSTMENT

Tighten Screw to Back Off

Application INCH Lbs. (N.m) Screw

Model 727 41 (4.6 N.m.) 2 Turns

Model 904 41 (4.6 N.m.) 7 Turns

Model 999 41 (4.6 N.m.) 4 Turns

TRANSMISSION THROTTLE CABLE/LINKAGE

NOTE: A special Idle Speed Actuator (ISA) Exerciser Box Tool is

required to initially set ISA motor and adjust transmission throttle linkage on vehicles with transmission model 999 with 4-cylinder engines.

727 Transmission with 6-Cylinder Engines

  1. Disconnect throttle control rod spring. Use spring to
    hold transmission throttle control lever forward, against stop. Block
    choke open and release fast idle cam.

  2. On carburetors equipped with throttle operated solenoid
    valve, turn key to "ON" position to energize solenoid. Open throttle
    halfway to allow solenoid to lock. Return throttle to idle position.

  3. Loosen retaining bolt on throttle control adjusting link.
    DO NOT remove spring clip or nylon washer. Pull on end of link to
    eliminate lash. Tighten link retaining bolt. Reconnect throttle
    control rod spring.

727 Transmission with V8 engines

1) Disconnect throttle control rod spring. Use spring to hold transmission throttle valve control lever against forward stop. Block choke open and release fast idle cam.

2) On carburetors equipped with throttle operated solenoid valve, turn key to "ON" position to energize solenoid. Open throttle halfway to allow solenoid to lock. Return throttle to idle position.

3) Loosen retaining bolt on throttle control rod adjusting link. Remove spring clip and slide nylon washer to rear of link. Push on end of link to eliminate lash and tighten retaining bolt. Install nylon washer and spring clip. Reconnect throttle control rod spring.

904 Transmission with 6-Cylinder Engines

  1. Remove air cleaner. Hold throttle control lever rearward
    against its stop. Block choke plate open and set carburetor linkage
    completely off fast idle cam.

  2. Unlock throttle control cable by lifting "T" shaped
    adjuster clamp with small screwdriver. Move cable outer sheath
    forward to remove any cable load on throttle cable bellcrank.

  3. Adjust cable by moving cable and sheath rearward until
    there is no lash between cable and throttle linkage. Lock cable by
    pressing "T" shaped clamp downward until clamp snaps into place.
    Install and reconnect any parts removed and/or disconnected.

999 Transmission with 4-Cylinder Engines

  1. Raise vehicle. Using a spring, hook one end on throttle
    control lever and other end on torque converter housing. Lower
    vehicle.

  2. Disconnect the ISA motor and connect Exerciser Box to
    ISA. Adjustment light should turn off and ready light should turn on.
    Press retrack button. Wait until ISA adjusts, ready light goes off
    and adjust light goes on.

3) Loosen bolt on throttle control link. Pull on link end to eliminate lash. Tighten adjusting bolt. Press extend button on Exerciser Box. When ISA retracts, release button and disconnect Exerciser Box. Connect ISA wiring and remove spring from throttle control lever. Install and reconnect any parts removed and/or disconnected.

999 Transmission with 6-Cylinder Engines

  1. Disconnect throttle control rod spring. Use spring to
    hold adjusting link in forward position, against nylon washer. Block
    choke open and release fast idle cam.

  2. Raise vehicle. Loosen both retaining bolts on adjusting
    link clamp. DO NOT remove spring clip or nylon washer. Use a spare
    spring to hold transmission throttle lever against forward stop.

  3. Push adjusting link to eliminate lash and pull clamp to
    rear so that bolt in rod bottoms in rear of slot in rod. Tighten
    forward clamp retaining bolt.

4) Pull throttle control rod to the rear so that bolt in rod bottoms in front of slot and tighten rear retaining bolt. Remove spare spring. Lower vehicle and reconnect throttle control rod spring.

AW-4 Transmission with All Engines

  1. With ignition off, retract cable self-adjusting mechanism
    fully. Press cable button down and push cable plunger inward.

  2. Rotate throttle lever to wide open throttle position.
    While holding throttle lever in position, allow cable plunger to
    extend. When plunger is fully extended, release throttle lever. Cable
    is now adjusted.

SHIFT LINKAGE

Cable Linkage

  1. Place gearshift lever in "P" position and raise vehicle.
    Using a small screwdriver, unlock shift control cable by releasing
    U-shaped cable adjuster clamp. Remove cable from mounting bracket.

  2. Move transmission shift lever rearward until fully
    seated into "P" detent. Ensure that driveshaft cannot be rotated.
    Snap control cable into cable mounting bracket and replace U-shaped
    cable adjuster clamp.

  3. Lower vehicle and verify engine starting. Engine should
    start only with shifter in "P" or "N" position.

Rod Linkage

  1. Loosen shift rod trunnion jam nuts at transmission lever.
    Remove shift rod-to-bellcrank lock pin. Disengage trunnion and shift
    rod. Place selector lever in "P" position and lock steering column.
    Move transmission shift lever to full rear Park position.

  2. Adjust shift rod trunnion to obtain free pin fit in
    bellcrank arm. Tighten jam nuts. On vehicles with shift lever on
    column, make sure linkage lash is eliminated by pulling down on shift
    rod and pushing up on outer bellcrank when tightening jam nuts.

  3. Check steering column lock for ease of operation. Ensure
    engine starts in "N" or "P", only. If starter engages in any drive
    gear, or does not work in "N" or "P", check for proper shift linkage
    adjustment or faulty neutral safety switch.

NEUTRAL SAFETY SWITCH

  1. Switch combines functions of neutral safety switch and
    back-up light switch. With transmission linkage properly adjusted,
    switch should allow starter operation in "P" and "N" only.

  2. To test switch, remove wire connector and test for
    continuity between center pin of switch and case. Continuity should

only exist when transmission is in "P" or "N".

  1. Check for continuity between 2 outer pins. Continuity
    should exist with transmission in "R" only. There should be no
    continuity between either outer pin and transmission case. If any of
    these conditions are not met, the switch should be replaced.

  2. To replace switch, unscrew from case. Move selector lever
    to "P" and "N" positions and check that switch operating fingers are
    centered in switch opening. Install switch and new seal in case.
    Check fluid level and add as needed.