GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Rear Driveshaft and U-Joints

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REMOVAL & INSTALLATION



See Figures 1, 2 and 3

DO NOT pound on the original propeller shaft yoke ears (unless the U-joints are being replaced) or the injected nylon joints may fracture.

  1. Raise and support the rear of the truck safely using jackstands.
  2.  
  3. Matchmark the relationship of the driveshaft-to-pinion flange and the slip yoke-to-front driveshaft or transmission/transfer case housing, as necessary. ALL shaft components which are being removed should be installed in their original positions, including slip yokes and U-joints ears. Disconnect the rear universal joint by removing its retainers. If the bearing caps are loose, tape them together to prevent dropping and loss of bearing rollers.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of a common single piece rear driveshaft mounting



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Fig. Fig. 2: Exploded view of a common two-piece rear driveshaft mounting

  1. If equipped with a one-piece driveshaft, perform the following procedures:
    1. Slide the driveshaft forward to disengage it from the rear axle flange.
    2.  
    3. Move the driveshaft rearward to disengage it from the transmission slip-joint, passing it under the axle housing.
    4.  

  2.  
  3. If equipped with a two-piece driveshaft, perform the following procedures:
    1. Slide the rear driveshaft half forward to disengage it from the rear axle flange.
    2.  
    3. Slide the driveshaft rearward to disengage it from slip-joint of the front driveshaft half, passing it under the axle housing.
    4.  
    5. Remove the center bearing support nuts and bolts.
    6.  
    7. Slide the front driveshaft half rearward to disengage it from the transfer case/transmission slip-joint.DO NOT allow the driveshaft to drop or allow the universal joints to bend to extreme angles, as this might fracture the injected joint internally. Support the propeller shaft during removal.To install:
    8.  

  4.  
  5. Inspect the slip-joint splines for damage, burrs or wear, for this will damage the transmission seal. Apply engine oil to all splined propeller shaft yokes.
  6.  
  7. DO NOT use a hammer to force the driveshaft into place. Check for burrs on the transmission output shaft spline, twisted slip yoke splines or possibly the wrong U-joint. Make sure the splines agree in number and fit. To prevent trunnion seal damage, DO NOT place any tool between the yoke and splines.
  8.  
  9. If installing a one-piece driveshaft, perform the following procedures:
    1. Align the matchmarks made during removal, then slide the driveshaft into the transmission/transfer case.
    2.  
    3. Align the rear universal joint-to-rear axle pinion flange, and make sure the bearings are properly seated in the pinion flange yoke.
    4.  
    5. Install the rear driveshaft-to-pinion fasteners and verify that all marks are aligned. Torque the fasteners to 15 ft. lbs. (20 Nm).

      Click image to see an enlarged view

      Fig. Fig. 3: View of a two-piece driveshaft assembly with components "in-phase" to prevent vibration

    6.  

  10.  
  11. If installing a two-piece driveshaft, perform the following procedures:
    1. Install the front driveshaft half into the transmission/transfer case (aligning the marks made during removal) and bolt the center bearing support in position. Torque the center bearing to support nuts and bolts to 25 ft. lbs. (34 Nm).In most cases, the yoke on the front driveshaft half must be bottomed out in the transmission (fully forward) before installation to the support.
    2.  
    3. Rotate the shaft as necessary so the front U-joint trunnion is in the correct position to align the matchmarks for the rear driveshaft half.Before installing the rear driveshaft, align the U-joint trunnions using the matchmarks made earlier. In some cases a "key" in the output spline of the front driveshaft half will align with a missing spline in the rear yoke.
    4.  
    5. Attach the rear U-joint to the axle, then torque the retainers to 15 ft. lbs. (20 Nm).
    6.  

  12.  
  13. Remove the jackstands and carefully lower the vehicle.
  14.  
  15. Road test the vehicle.
  16.  

U-JOINT REPLACEMENT



See Figures 4, 5, 6, 7, 8, 9 and 10

As mentioned earlier in this section, these vehicles utilize 2 different types of U-joint assemblies. At the factory, most vehicles are equipped with a nylon injected assembly. Because these assemblies contain no snapring grooves, and the very action of removing them destroys their retainers, they cannot be reused. Once removed, nylon injected U-joints should be discarded. If your vehicle has already received U-joint service, then it will be equipped with a snapring retained assembly. Once properly removed, these assemblies may be reused if they are in good condition.

Snapring Type
  1. Matchmark and remove the driveshaft assembly from the vehicle. Refer to the procedure earlier in this section.
  2.  


WARNING
NEVER clamp the driveshaft tube in a vise, for this may dent the tube. Support the driveshaft horizontally and clamp on the yokes of the universal joints using a soft-jawed vise or blocks of wood to protect the yokes.

  1. Remove the snaprings from the yoke by pinching the ends together with a pair of pliers. If the snapring is difficult to remove, tap the end of the bearing cap lightly to relieve pressure from the snapring.
  2.  
  3. Support the propeller shaft horizontally in line with the base plate of a bench vise, but never clamp the driveshaft tube.
  4.  



Click image to see an enlarged view

Fig. Fig. 4: Exploded view of a replacement U-joint assembly - internal snapring type



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Fig. Fig. 5: Exploded view of a replacement U-joint assembly - external snapring type



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Fig. Fig. 6: Production Nylon type U-joint

  1. Place the universal joint so the lower ear of the yoke is supported on a 1 1 / 4 in. or 1 1 / 8 inch socket (or ID pipe), depending on the application. Most rear driveshafts and late model driveshafts require the 1 1 / 8 in support. Press the trunnion bearing against the socket/pipe in order to partially press it from the yoke. A cross press such as tool J-9522-3 or equivalent should be used for this.
  2.  
  3. Grasp the cap and work it out. If necessary, use tool J-9522-5 or an equivalent spacer to further push the bearing cap from the trunnion, then grasp and work it free.
  4.  
  5. Rotate the shaft and support the other side of the yoke, then press the bearing cap from the yoke as in previous steps.
  6.  
  7. Remove the trunnion from the driveshaft yoke.
  8.  
  9. Clean and check the condition of all parts. Use U-joint repair kits to replace all the worn parts or replace the assembly using a new U-joint.
  10.  

If the used universal joints are going to be reinstalled, repack with new grease.

To install:
  1. Repack the bearings with chassis grease and replace the trunnion dust seals after any operation that requires disassembly of the U-joint. Be sure the lubricant reservoir at the end of the trunnion is full of lubricant. Fill the reservoirs with lubricant from the bottom.
  2.  



Click image to see an enlarged view

Fig. Fig. 7: Pressing out the U-joint bearing cap



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Fig. Fig. 8: Positioning the spacer tool to assist in bearing cap removal

  1. Partially insert the cross into the yoke so one trunnion seats freely in the bearing cap, then rotate the shaft so this trunnion is on the bottom.
  2.  
  3. Install the opposite bearing cap part way. Be sure both trunnions are started straight into the bearing caps.
  4.  
  5. Press against opposite bearing caps, working the cross constantly to be sure the trunnions are free in the bearings. If binding occurs, check the needle rollers to be sure one or more needles have not become lodged under an end of the trunnion.
  6.  
  7. As soon as one bearing retainer groove is exposed, stop pressing and install the bearing retainer snapring.
  8.  

It may be necessary to strike the yoke with a hammer to align the seating of the bearing retainers.

  1. Continue to press until the opposite bearing retainer can be installed. If difficulty installing the snaprings is encountered, tap the yoke with a hammer to spring the yoke ears slightly.
  2.  
  3. Once the driveshaft and U-joints are properly assembled, align the matchmarks and install the driveshaft to the vehicle.
  4.  



Click image to see an enlarged view

Fig. Fig. 9: Installing the snaprings



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Fig. Fig. 10: Tapping the yoke in order to seat the retaining clip

Nylon Injected Type

Don't disassemble these joints unless replacing the complete U-joint. These factory installed joints cannot be reused and should instead be replaced by snapring type U-joints.

  1. Matchmark and remove the driveshaft assembly from the vehicle. Refer to the procedure earlier in this section.
  2.  


WARNING
NEVER clamp the driveshaft tube in a vise, for this may dent the tube. Support the driveshaft horizontally and clamp on the yokes of the universal joints using a soft-jawed vise or blocks of wood to protect the yokes.

  1. Support the driveshaft horizontally in line with the base plate of a bench vise, but never clamp the driveshaft tube.
  2.  
  3. Place the universal joint so the lower ear of the yoke is supported on a 1 1 / 4 in. or 1 1 / 8 inch socket (or ID pipe), depending on the application. Most rear driveshafts and late model driveshafts require the 1 1 / 8 in support.
  4.  
  5. Press the lower bearing cap out of the yoke ear, this will shear the nylon injected ring retaining the lower bearing cap.
  6.  
  7. If the bearing cap is not completely removed, lift the cross (J-9522-3) and insert J-9522-5 or equivalent spacer, then press the cap completely out.
  8.  
  9. Rotate the driveshaft, shear the opposite plastic retainer, and press the other bearing cap out in the same manner.
  10.  
  11. Remove the cross from the yoke.
  12.  

Production U-joints cannot be reassembled. There are no bearing retainer grooves in the caps. Discard all parts that were removed and substitute those in the overhaul kit.

  1. If the front U-joint is being removed, separate the bearing caps from the slip yoke in the same manner.
  2.  
  3. Remove the sheared plastic bearing retainer from the yoke. If necessary, drive a small pin or punch through the injection holes to aid removal.
  4.  
  5. Install the new snapring U-joints. Refer to the snapring type installation procedure found earlier in this section.
  6.  

 
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