TRANSFER CASE - OVERHAUL (207/231)

1988 Jeep Cherokee

1983-96 TRANSFER CASES

Chrysler Corp., GM Corp., Jeep - New Process 207 & 231

Dodge; B1500 & Dakota

GMC/Chevrolet; "T" Series (Blazer & Jimmy)

Jeep; Cherokee, Comanche, Grand Cherokee, Wagoneer, Wrangler

IDENTIFICATION

Transfer case can be identified by an I.D. tag, located on rear case. I.D. tag provides model number, serial number and low range ratio. Date of manufacture is the serial number (I.D. number). This information is necessary when ordering parts.

DESCRIPTION

Model 231 transfer case is a part time, chain-driven, 4-position unit with 2-piece aluminum case. Torque input in 4WD high and low range is undifferentiated. 2WD operation is achieved by a vacuum shift motor. Shift motor disconnects right front axle when 2WD is selected. Vacuum shift motor is controlled by a vacuum switch located on front of transfer case and actuated by shift sector.

ADJUSTMENTS

GEARSHIFT LINKAGE

Chrysler Corp.

Shift transfer case to 2H position. Raise and support vehicle. Loosen lock bolt at trunnion. Ensure linkage rod slides freely in trunnion. Verify transfer case range lever is fully engaged in 2H position. Tighten lock bolt at trunnion. Lower vehicle. Check shift linkage operation. Ensure transfer case shifts into and operates properly in all gear ranges.

General Motors

Remove shift lever knob retainer. Remove shift lever knob. Remove floor console. Place shift lever in Neutral. Pry control cable end from shift lever. Loosen control cable lock nut. Check transfer case to ensure it is in Neutral. Ensure shift lever is in Neutral. Turn shift lever end of cable in or out as needed until it is aligned with shift lever. Install control cable on shift lever. Tighten control cable lock nut.

Jeep

Shift transfer case to 4L position. Raise and support vehicle. Loosen lock bolt at trunnion. Ensure linkage rod slides freely in trunnion. Verify transfer case range lever is fully engaged in 4L position. Tighten lock bolt at trunnion. Lower vehicle. Check shift linkage operation. Ensure transfer case shifts into and operates properly in all gear ranges.

TESTING

VACUUM SWITCH

Shift to 2WD position. Locate vacuum switch on front of

transfer case. Apply 15 in. Hg vacuum to "L". See Fig. 1. Vacuum should be present at "M". Connect a vacuum gauge to "N". Shift to 4WD position. Apply vacuum to "L". Vacuum should be present at "N". If switch fails any test, replace switch.

_92F13081

Fig. 1: Testing Vacuum Switch Courtesy of Chrysler Corp.

TROUBLE SHOOTING

SYMPTOM DIAGNOSIS

Will Not Shift Or Difficult To Shift Into Gear Vehicle speed too high; slow vehicle to 2-3 MPH to shift. Vehicle operated too long on dry paved surface; stop vehicle and place in Reverse or Neutral to relieve driveline torque. Ensure transfer case external linkage is not binding. Ensure correct fluid is used. Internal parts may be worn or damaged.

Noisy In All Gears

Check fluid level. Ensure correct fluid is used. If fluid is okay, locate possible internal mechanical problem.

Jumps Out Of Gear Or Noisy In 4WD

Transfer case not completely in gear; check shift linkage. Range fork damaged. Shift fork pads are worn or shift fork binding. Low range gear worn.

Fluid Leaking From Vent Or Seals

Transfer case overfilled. Vent plugged. Output shaft seals are damaged or not installed properly.

ON-VEHICLE SERVICE

FRONT OIL SEAL

Removal & Installation

1) Mark front drive shaft and flange for installation

alignment reference. Remove front drive shaft. Remove flange. Discard washer and nut. Using a screwdriver, carefully remove oil seal. Ensure seal contact surface is clean.

2) Apply ATF to seal lip and flange seal surface. Install NEW
oil seal. Install flange and NEW washer and nut. Tighten nut to
specifications. See TORQUE SPECIFICATIONS. Install front drive shaft
using alignment marks. Check transfer case fluid.

EXTENSION HOUSING OIL SEAL & BUSHING

Removal & Installation

1) Mark rear drive shaft and flange for installation

alignment reference. Remove rear drive shaft. Tap extension housing in a clockwise direction and remove extension housing. DO NOT pry on extension housing. Using a screwdriver, remove oil seal from extension housing.

2) Using bushing driver, replace bushing in extension
housing. Install NEW extension housing oil seal. Apply silicone
sealant to extension housing mating surface. Install extension
housing. To complete installation, reverse removal procedure.

REMOVAL & INSTALLATION

TRANSFER CASE

Removal

10. Shift transfer case into 4H and disconnect battery
    negative cable. Raise vehicle, remove skid plate and drain fluid.

11. Mark front and rear output shaft yokes to drive shafts for
    reassembly reference. Support transfer case and remove rear
    crossmember. Remove drive shafts.

12. Disconnect vehicle speed sensor electrical connector and
    vacuum (hoses) harness at transfer case. Remove shift lever or linkage
    rod from case. Remove transfer case attaching bolts. Remove transfer
    case from vehicle.

Installation

10. Clean all old gasket material from transmission and
    transfer case mating surfaces. Position NEW gasket on transfer case
    with orientation tab at upper left bolt hole.

11. Install transfer case, aligning splines of input shaft
    with transmission. Slide transfer case forward until seated against
    transmission. Install transfer case attaching bolts and tighten to
    specification. See TORQUE SPECIFICATIONS. Install rear crossmember.

12. Attach shift lever and connect speed sensor electrical
    connector and vacuum harness at transfer case. Using reference marks
    made during removal, reinstall front and rear drive shafts. Refill
    transfer case. Install skid plate and lower vehicle. Connect negative
    battery cable. Road test vehicle.

TRANSFER CASE DISASSEMBLY

10. Remove front companion yoke. See Fig. 2 or 3. Discard
    washer and nut. Shift transfer case to 4L and remove extension
    housing. Remove rear bearing snap ring. Using 2 screwdrivers under
    each tab, remove retainer housing. Remove rear case and oil pump as an
    assembly.

11. Remove oil pump pick-up screen and tube from rear case.
    Remove oil pump. Remove "O" ring from oil pump and discard. DO NOT
    separate oil pump halves. Pump must be replaced as an assembly if
    necessary.

12. Remove mode spring. Using a soft hammer, tap front output
    shaft upward and remove with drive chain as an assembly. Remove
    mainshaft, mode fork and shift rail as an assembly. Remove mode fork
    and shift rail from synchronizer sleeve.

13. Mark synchronizer sleeve position for reassembly
    reference. Remove synchronizer sleeve from mainshaft. Remove
    synchronizer hub snap ring. Remove synchronizer hub, stop ring and
    drive sprocket. Slide range fork pin out of sector.

14. Remove range fork and shift hub as an assembly. Remove
    range lever from sector shaft. Remove shift sector, bushing and "O"
    ring. Remove shift detent pin, spring and plug. Remove front bearing
    retainer. Remove input gear snap ring.

15. Press input and low range gear assembly from input gear
    bearing. Remove low range gear snap ring. Remove input gear retainer,
    thrust washers and input gear from low range gear.

16. Remove all oil seals. Remove magnet from front case.
    Remove front bearing snap ring. Using a plastic hammer, remove front
    bearing. Press input gear bearing from front case.

17. Using slide hammer and internal puller, remove input gear
    pilot bearing. Press bearings from drive sprocket. Using internal
    puller and slide hammer, remove output shaft rear bearing.

18. 24 25 26

    
    

    10. Front Companion Flange Nut

    11. Front Companion Flange Seat

    12. Front Companion Flange

    13. Front Output Shaft Seal

    14. Snap Ring

    15. Front Output Shaft Bearing

    16. Case Plug

    17. Vacuum Switch

    18. Gasket

    
    

    10. Front Case

    11. Low Range Lock Plate

    12. Input Gear Seal

    13. Input Gear Front Bearing

    14. Input Gear Rear Bearing

    15. Thrust Bearing Washer

    16. Input Gear Thrust Bearing

    17. Input Gear

    18. Input Gear Cup Plug

    19. Mainshaft Pilot Bearing

    20. Planetary Thrust Washer

    21. Annulus Gear

    22. Front Thrust Ring

    23. Planetary Gear

    24. Rear Thrust Ring

    25. Planetary Retaining Ring

    
    

    
    

    10. Snap Ring

    11. Synchronizer Front Spring

    12. Synchronizer Struts

    13. Synchronizer Hub

    14. Synchronizer Rear Spring

    15. Synchronizer Sleeve

    16. Synchronizer Stop Ring

    17. Mainshaft

    18. Thrust Washer

    19. Drive Sprocket Rear Bearing

    20. Drive Sprocket Front Bearing

    21. Drive Chain

    22. Drive Sprocket

    23. Front Output Shaft Bearing

    24. Front Output Shaft

    25. Range Fork Pads

    26. Range Fork Front Bushing

    27. Range Fork

    28. Range Fork Rear Bushing

    29. Shift Rail

    30. Shift Rai! Bracket

    31. Mode Fork Pads

    32. Mode Fork Front Bushing

    Fig. 2: Exploded View Of Transfer Case (Model 207) Courtesy of Chrysler Corp.

    
    Mode Fork

19. Mode Fork Cup

20. Mode Fork Spring

21. Mode Fork Rear Bushing

22. Rear Case

23. Oil Pump

24. Speedometer Drive Gear

25. Pump Housing Seal

26. Oil Pump Housing

27. Mainshaft Rear Bearing

28. Rear Bearing Snap Ring

29. Rear Retainer

30. Vent Assembly

31. Extension Housing

32. Extension Housing Seal

33. Fill Plug

34. Drain Plug

35. Magnet

36. Shift Sector

37. Spacer

38. Sector Detent Spring

39. Detent Spring Bolt

40. Range Lever Nut

41. Range Lever

42. "O" Ring Retainer

43. "O" Ring

95H2941C

10. Front Companion Yoke,
    Nut, Washer & Seal

11. Detent Plug, Spring & Pin

12. Front Retainer & Seal

13. Front Case

14. Vacuum Switch & Seal

15. Vent Assembly

16. Input Gear Bearing & Snap Ring

17. Low Range Gear Snap Ring

18. Input Gear Retainer

10. Low Range Gear Thrust Washers

11. Input Gear

12. Input Gear Pilot Bearing

13. Low Range Gear

14. Range Fork Shift Hub

15. Synchronizer Hub Snap Ring

16. Synchronizer Hub Springs

17. Synchronizer Hub & Inserts

18. Synchronizer Sleeve

19. Synchronizer Stop Ring

20. Snap Ring

21. Output Shaft Front Bearing

22. Front Output Shaft

10. Drive Sprocket

11. Drive Chain

12. Drive Sprocket Bearings

13. Output Shaft Rear Bearing

14. Mainshaft

15. Oil Seal

16. Oil Pump Assembly

17. Rear Bearing

18. Snap Ring

19. Rear Case

20. Fill Plug

21. Drain Plug

22. Rear Retainer

10. Extension Housing

11. Bushing

12. Oil Seal

13. Oil Pick-Up Screen

14. Tube Connector

15. Oil Pick-Up Tube

16. "O" Ring

17. Magnet

18. Range Lever Nut & Washei

19. Range Lever

20. "O" Ring & Seal

21. Sector

22. Mode Spring

23. Mode Fork

24. Mode Fork Pads

25. Range Fork Pads

26. Range Fork Bushings

27. Range Fork

92 H13083

Fig. 3: Exploded View Of Transfer Case (Model 231) Courtesy of Chrysler Corp.

CLEANING & INSPECTION

Clean all parts with solvent. Dry with compressed air. Replace all oil seals, "O" rings and snap rings. Check all parts for wear or damage. Replace all worn or damaged parts. If low range annulus gear inside front case is damaged or worn, front case and gear must be replaced as an assembly. Replace oil pump as an assembly if any part is damaged or worn.

TRANSFER CASE REASSEMBLY

NOTE: When installing bearings, ensure bearing bores are aligned with oil feed holes.

1) Lubricate all parts with Dexron III before installing.

Install output shaft front bearing with NEW snap ring. Install output shaft oil seal in front case. Install snap ring on NEW input gear bearing. See Fig. 2 or 3.

10. Press input gear bearing so snap ring is seated against
    case. Using press, install NEW input gear pilot bearing. Assemble low
    range gear, input gear, thrust washers and retainer.

11. Install snap ring. Ensure snap ring is seated in low range
    gear groove. Start input gear shaft into bearing in front case. Press
    input shaft gear into bearing.

CAUTION: DO NOT press against end surfaces of gear. Failure to use proper size tool could lead to gear case or thrust washer damage.

10. Install input gear snap ring. Install oil seal in front
    bearing retainer. Apply a 1/8" bead of silicone sealant to retainer
    mating surface. Align oil channel in retainer with oil feed hole in
    case. Install retainer on case. Tighten bolts to specification.

11. Install sector shaft "O" ring and bushing. Install range
    sector in case. Install range lever and nut. Install detent, detent
    spring and plug. Tighten to specification. See TORQUE SPECIFICATIONS.
    Install NEW pads and fork rail bushings on range fork. Install range
    fork and shift hub.

12. Ensure range fork pin is engaged with range sector slot.
    Press front bearing in drive sprocket until bearing is flush with bore
    edge. Install rear bearing until bearing is 3/16" below bore edge. See
    Fig. 4.

13. Install inserts and spring in synchronizer hub. Install
    sprocket on mainshaft. Install synchronizer stop ring on mainshaft.
    Ensure stop ring is seated. Install synchronizer hub on mainshaft.
    Align and seat hub inserts on stop ring lugs. Install synchronizer hub
    snap ring.

14. Install synchronizer sleeve on hub. Ensure sleeve is
    positioned so beveled spline ends are facing stop ring. Ensure sleeve
    tooth is aligned (centered) over each synchronizer strut. Gear clash
    will occur if strut and sleeve teeth are misaligned. Install NEW pads
    on mode fork. Engage mode fork in synchronizer sleeve. Install
    mainshaft and fork assembly in case. Ensure mode fork shift rail is
    seated in both range fork bushings.

15. Install output shaft and drive chain assembly. Install
    mode spring on shift rail. Using bearing driver, install output shaft
    rear bearing. Lubricate bearing after installation. Install seal in
    oil pump feed housing. Install oil pump in housing. Tighten to
    specification.

10. Install oil pick-up tube "O" ring in oil pump. Prime oil
    pump by pouring ATF into pump through pick-up tube opening. Install
    oil pump and pick-up tube in case. Ensure oil screen is properly
    positioned. See Fig. 5. Install magnet in front case. Apply 1/8" bead
    of silicone sealer to front case. Install rear case. Tighten to
    specification. See TORQUE SPECIFICATIONS. Ensure mainshaft splines are
    engaged with oil pump inner gear and a washer is used on bolts at
    dowel locations.

11. Install rear bearings in retainer. Apply 1/8" bead of
    silicone sealer and install retainer to case. Install rear retainer
    snap ring. Install extension housing. Install front companion yoke.
    Install NEW gasket on vacuum switch. Install vacuum switch in case.
    Fill transfer case with Dexron III.

92G13082

Fig. 4: Installing Drive Sprocket Bearings Courtesy of Chrysler Corp.

Fig. 5: Identifying Oil Pump Screen Position Courtesy of Chrysler Corp.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS TABLE

Application Ft. Lbs. (N.m)

Companion Flange Nut

Chrysler Corp 130-200 (176-271)

General Motors 80 (108)

Jeep 110 (149)

Detent Plug

General Motors 11 (15)

Chrysler Corp. & Jeep 15 (20)

Drain & Fill Plug 30-40 (41-54)

Extension Housing Bolt 20-25 (27-34)

Front Bearing Retainer Bolt

Chrysler Corp. & Jeep 16 (22)

General Motors 14 (19)

Front Case-to-Rear Case Bolt Chrysler Corp.

Flange Head Bolt 35-45 (47-61)

All Other Bolts 20-25 (27-34)

General Motors 23 (31)

Jeep 20-25 (27-34)

Range Lever Nut 15-20 (20-27)

Rear Bearing Retainer Bolt 20-25 (27-34)

Rear Crossmember 30 (41)

Shift Lever Lock Bolt 10 (14)

Speed Sensor Bolt 23 (31)

Transfer Case-to-Transmission Nut 26 (35)

Vacuum Switch

Chrysler Corp 15-25 (20-34)

General Motors 17 (23)

Jeep 20-25 (27-34)

INCH Lbs.
Control Cable Lock Nut 18 (2)

VACUUM DIAGRAMS

For vacuum diagrams, refer to appropriate VACUUM DIAGRAMS article in the ENGINE PERFORMANCE section.