Chrysler Full-Size Trucks 1989-1996 Repair Guide

Dana Differential Overhaul

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It is not necessary to remove the complete axle assembly from the vehicle for differential service.

DISASSEMBLY



  1. Raise and safely support the rear of the vehicle on the frame rails in front of rear spring. This will allow the axle assembly to hang free for more working room. Remove the axles and driveshaft. Thoroughly clean the outer area of the housing and axle tubes with a safe cleaning solvent and wipe dry.
  2.  
  3. Place a drain pan under the differential. Remove the cover and drain the lubricant.
  4.  
  5. If equipped with a Trac-Lok differential, do not perform this step. Wash and flush the internal components of the differential. Allow them to dry.
  6.  
  7. Install a pilot stud and attach a dial indicator. Locate the plunger slightly at a right angle to the back of the ring gear. Zero the dial indicator.
  8.  
  9. Rotate the ring gear several times. Mark the ring gear and differential case flange at the maximum run-out point. The mark on the case flange will be very useful when measuring differential case run-out. If the combined ring gear run-out exceeds 0.006 in. (0.15mm), possible causes could be a loose ring gear or damaged case.
  10.  
  11. Check the clearance between the differential bearing cap and bearing cup by trying to insert a 0.003 in. (0.076mm) thick feeler gauge between them. The 0.003 in. (0.076mm) blade should not enter between the two surfaces. If the clearance is more than 0.003 in. (0.076mm), the cause could be the bearing cup rotated in the housing seat and caused excessive wear.
  12.  
  13. Note the position reference marks stamped on the bearing caps and machined housing sealing surface.
  14.  
  15. Remove the bearing caps. Install a position spreader on the differential housing with the tool dowel pins in the proper locating holes. Install the hold-down clamps and tighten the turn-buckle finger-tight.
  16.  
  17. Install a pilot stud at the left side of the differential housing. Attach a dial indicator to the housing pilot stud. Load the indicator plunger against the opposite housing and zero the indicator.
  18.  
  19. Separate the housing enough to remove the case from the housing. DO NOT separate the case more than 0.015 in. (0.038mm) with the spreader tool. Measure the distance with the dial indicator.
  20.  
  21. When the separating distance is reached, remove the dial indicator. Pry the differential case loose from the housing. To prevent damage, pivot on the housing with the end of the pry bar against the case.
  22.  
  23. Remove the case from the housing. Retain the differential bearing cups and bearings as matched sets if they are to be used over again.
  24.  
  25. Clamp the differential in a soft jawed vise. Remove and discard the ring gear mounting bolts. Tap the ring gear with a soft mallet to remove it.
  26.  
  27. If the ring gear run-out exceeded 0.006 in. (0.15mm), the case flange run-out should be measured at this time.
  28.  
  29. Install the case, with the original bearings, into the housing. Remove the spreader. Install the bearing caps and tighten the mounting bolts finger tight.
  30.  
  31. Set up the dial indicator with the plunger on the inner side of the case flange. Zero the plunger.
  32.  
  33. Rotate the flange several times and observe the reading. The flange maximum run-out should not exceed 0.003 in. (0.076mm). It is possible to reduce excessive ring gear run-out by positioning maximum run-out mark located 180° opposite the flange maximum run-out. Remove the case from the housing.
  34.  
  35. Remove the pinion yoke nut and washer. Use a puller and remove the yoke from the pinion shaft.
  36.  
  37. Remove the pinion seal. Remove the oil slinger, front bearing and shims. Record the thickness of the shims. This will save time should the shims be misplaced.
  38.  
  39. Remove the pinion gear and rear bearing from the housing.
  40.  
  41. Use an appropriate puller and remove the front bearing cup from housing.
  42.  
  43. Use an appropriate puller and remove the rear bearing cap from the housing.
  44.  
  45. Remove the depth shims from the housing. Record the thickness of the shims.
  46.  
  47. Remove the rear bearing from the pinion shaft, using the appropriate puller.
  48.  
  49. Clamp the differential case in a soft-jawed vise. Use a pin punch to remove the pinion gear mate shaft lock pin from the case.
  50.  
  51. Remove the pinion gear mate shaft. Remove the differential pinion gears and thrust washers.
  52.  
  53. Remove the differential side gears and thrust washers.
  54.  
  55. Remove the case from the vise.
  56.  
  57. Remove the end bearings from the case using the appropriate puller. Take care not to damage the bearing cage.
  58.  
  59. Remove the bearing shims from the case hubs. Mark them for assembly reference. Record the shim thickness.
  60.  
  61. Wash and clean all of the differential components in a safe solvent. Do not steam clean.
  62.  
  63. Clean the axle shaft tubes. Pull a rag attached to a wire through the tubes. Inspect all of the component parts.
  64.  
  65. Replace any worn parts. Cup and bearings must be replaced as matched sets only.
  66.  

ASSEMBLY



  1. Lubricate all of the differential components with hypoid gear lubricant.
  2.  
  3. Install the differential side gears and thrust washer, the pinion gears and thrust washers, and the gear mate shaft into the differential case.
  4.  
  5. Insert and seat the lock pin in the case and shaft. If replacement gears and thrust washers were installed, it is not necessary to measure the gear backlash. Correct fit is due to close machining tolerances during manufacture.
  6.  
  7. Position and align the ring gear threaded hole to the case flange. Install but do not tighten new ring gear bolts. After the bolts are threaded into the ring gear bolt holes, tap the ring gear with a non-metallic mallet. Make sure the gear is flush against the carrier flange.
  8.  
  9. Clamp the differential case in a soft jawed vise. Alternately tighten each ring gear bolt to 81 ft. lbs. (110 Nm).
  10.  
  11. Place a set of dummy bearing special tools on each case bearing hub.
  12.  
  13. Install the differential spreader and dial indicator on the housing. Spread the housing. Take care not to exceed the maximum of 0.015 in. (0.38mm).
  14.  
  15. Remove the dial indicator. Install the ring gear case assembly in the housing.
  16.  
  17. Remove the spreader. Observe the assembly reference marks and locate the bearing caps in their original positions.
  18.  
  19. Set up the dial indicator to against the back side of the ring gear. Insert a small pry bar between the bearing cap and the left side of the differential case. Pry the case to the left and record the travel distance.
  20.  
  21. The measurement is the shim thickness required for case zero end-play. The total thickness will be determined during the ring gear backlash adjustment.
  22.  
  23. Remove the dial indicator. Remove the bearing caps.
  24.  
  25. Spread the housing and remove the differential case.
  26.  
  27. If the original ring and pinion gear are not reusable, the pinion gear depth shim thickness must be determined before installing the differential case.
  28.  
  29. To determine the gear depth a special tool set such as D-271 is used. The following is the procedure using the tool set:49. Insert Master Pinion Block D-120 into the pinion bore. Place Disc D-116-2 on Arbor D-115-3 and position in the bearing cradles. This is the centerline of the ring gear/axle shaft. Place Pinion Height Block D-116-1 on top of master pinion block tool and against arbor tool. Firmly place Gauge Block D-115-2 and dial indicator D-1-6-5 on the lowest step of the pinion height block tool. Zero the dial indicator point. Move the gauge block toward the arbor until the indicator contacts the arbor tool. Slide the gauge block across along the arbor while observing the indicator. Record the longest travel distance, whether inward (-) or outward (+) as indicated by the pointer. The plunger distance indicated, plus or minus the variance etched in the gear is the required thickness for the depth shims. Measure the thickness of each depth shim with a micrometer and combine the shims necessary for total required pack thickness. Include the oil slinger thickness with the total shim pack thickness. Remove the measurement tools from the differential housing. Place the depth shims in the pinion gear rear bearing bore. Install the rear pinion bearing cup. Install the front bearing cup. Install the rear pinion bearing completely seated on the pinion shaft using an appropriate press.
  30.  
  31. Install the pinion gear into the housing. Install the front pinion bearing, oil slinger, yoke, washer and nut. Tighten the yoke nut until it requires 10 inch lbs. (1 Nm) tighten to rotate the pinion gear. This will seat the bearings.
  32.  
  33. Measure the pinion gear depth of mesh. Place the height block on the face of the pinion gear. Place the arbor and discs into the bearing cradles. Firmly place the gauge block with the indicator on the lowest step of the height block. Zero the dial indicator.
  34.  
  35. Move the gauge block toward the arbor until the indicator contacts the arbor tool. Slide the gauge block across along the arbor while observing the indicator. Record the longest travel distance, whether inward (-) or outward (+), indicated by the pointer.
  36.  
  37. If the indicator reading actual depth is within 0.002 in. (0.05mm) of variance etched, it is acceptable. If not within specs, correct the shim pack thickness.
  38.  
  39. Remove the measuring tools. Remove the pinion gear nut, washer, yoke, oil slinger and front bearing.
  40.  
  41. Install the shims that were removed during disassembly. Install the front bearing and oil slinger.
  42.  
  43. Lubricate the pinion bearing and install it.
  44.  
  45. Install the pinion yoke, washer and new pinion nut. Tighten the nut to 250-270 ft. lbs. (330-366 Nm).
  46.  
  47. Check the preload torque. The torque necessary to turn the pinion shaft should be between 10-20 inch lbs. (1-3 Nm).
  48.  
  49. If the preload torque is not within specs, correct the shim thickness accordingly. To increase torque, decrease the shim thickness. To decrease the torque, increase the shim thickness.
  50.  
  51. To check the ring gear backlash:
    1. Spread the housing. Install the dummy bearing special tools on the case hubs. Position the case in the differential housing and install the bearing caps finger tight. Remove the spreader.
    2.  
    3. Install a pilot stud and dial indicator on the housing. Load the indicator against the back of the ring gear. Ensure that the ring and pinion gears are tightly meshed. Zero the dial indicator.
    4.  
    5. Insert a small pry bar between the bearing cap and the left side of the case. Pry the ring gear and case toward the right side away from the pinion gear. Observe the dial indicator reading. Repeat the measurement several times to check consistency. Record the travel distance.
    6.  
    7. The measurement shows shim thickness necessary to eliminate ring gear backlash. Subtract this thickness from the case zero end-play shim thickness. The shims must be placed on the ring gear side between the case and the bearing.
    8.  

  52.  
  53. Remove the dial indicator and stud.
  54.  
  55. Remove the bearing caps. Spread the housing and remove the case assembly. Remove the dummy bearing special tools from the case hub ends.
  56.  
  57. Position the determined backlash shims in position on the ring gear side of the case hub and install the bearing. Place the remaining zero end-play shims on the other case hub, include and 0.015 in. (0.38mm) additional shim to provide the required preload, and install the bearing. Match the bearing to cups and install the cups over the bearings.
  58.  
  59. Spread the housing and install the differential case assembly.
  60.  
  61. Remove the spreader. Install the bearing caps in their proper locations by aligning the reference marks. Tighten the mounting bolts to 70-90 ft. lbs. (95-122 Nm).
  62.  
  63. Measure the backlash at three equally spaced locations.
  64.  
  65. The gear backlash must be within 0.004-0.009 in. (0.10-0.23mm). It cannot vary by more than 0.002 in. (0.05mm) between the points checked.
  66.  
  67. Excessive backlash is corrected by moving the ring gear teeth closer to the pinion. Insufficient backlash is corrected by moving the ring gear away from the pinion gear. Backlash correction is accomplished by transferring shims from one side to the other.
  68.  
  69. Install the axles. Install the housing cover with a silicone sealer bead as a gasket. Fill the differential with the correct amount of lubricant and install the filler plug. Lower the vehicle. Test the brakes and axle for proper operation.
  70.  

TRAC-LOK SERVICE



Limited slip Trac-Lok is an option with the Model 60 axle. The Trac-Lok differential uses the same internal components as the standard Model 60 plus two clutch disc packs. With the exception of the ring gear, pinion, pinion bearings and differential side bearings, the differential case and internal parts are serviced as an assembly only and should not be disassembled. Should the differential be submerged in water, the axle lubricant must be replaced immediately. Fluid change is described in Routine Maintenance . Four ounces of Mopar® Hypoid Gear Lubricant additive or equivalent should be added. The additive contains a friction modifier for the limited slip clutches. After a fluid change, drive the vehicle and make several slow figure eight turns. This maneuver will pump the lubricant through the clutch discs.

 
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