Chevrolet Full Size Cars 1979-1989

Driveline

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Fig. Fig. 1 Exploded view of a common driveshaft and U-joint assembly

Full size Chevrolet driveshafts are of the conventional, open type. Located at either end of the driveshaft is a U-joint or universal joint, which allows the driveshaft to move up and down to match the motion of the rear axle. The front U-joint connects the driveshaft to a slip jointed yoke. This yoke is internally splined, and allows the driveshaft to move in and out on the transmission splines. The rear U-joint is clamped or bolted to a companion flange fastened to the rear axle drive pinion. The rear U-joint is secured in the yoke in one of two ways. Dana and Cleveland design driveshafts (typically found on 1979-81 vehicles) use a conventional type snapring to hold each bearing cup in the yoke. The snapring fits into a groove located in each yoke end, just on top of the bearing cup. A Saginaw design driveshaft (usually found on 1982 and later vehicles, but which were in use from 1979 on) secures the U-joints differently. Nylon material is injected through a small hole in the yoke during manufacture, and flows along a circular groove between the U-joint and the yoke creating a non-metallic snapring. The Nylon joints are sheared during removal and replaced with conventional snapring types, so your vehicle may not contain the Nylon joints if they have been removed previously.

There are two methods of attaching the rear U-joint to the rear axle. One method employs a pair of straps, while the other method is a set of bolted flanges. Band U-joints, requiring replacement, will produce a clunking sound when the car is put into gear and when the transmission shifts from gear to gear. This is due to worn needle bearings or a scored trunnion end possibly caused by improper lubrication during assembly. U-joints require no periodic maintenance and therefore have no lubrication fittings.

Some driveshafts, generally those in heavy duty applications, use a damper as part of the slip joint. This vibration damper cannot be serviced separately from the slip joint. If either component goes bad, the two must be replaced as a unit.

REMOVAL & INSTALLATION


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Fig. Fig. 2 Driveshaft flange attachment



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Fig. Fig. 3 Strap-type driveshaft retainer

  1. Raise the rear of the vehicle and support it safely using jackstands.
  2.  
  3. Matchmark the relationship of the driveshaft to the differential flange to assure that they are reassembled in the same position.
  4.  
  5. Disconnect the rear U-joint by removing the U-bolts or retaining straps.
  6.  
  7. To prevent the loss of the needle bearings, tape the bearing caps in place. If you are replacing the U-joint, this is not necessary.
  8.  
  9. Remove the driveshaft from the transmission by sliding it rearward. There may be some oil leakage from the rear of the transmission. It can be contained by placing a small plastic bag over the rear of the transmission and holding it in place with a rubber band. To install:
  10.  
  11. Insert the front yoke into the transmission so that the driveshaft splines mesh with the transmission splines.
  12.  
  13. Using the reference marks made earlier, align the driveshaft with the differential flange and secure it with the U-bolts or retaining straps.
  14.  
  15. Remove the jackstands and carefully lower the vehicle.
  16.  

U-JOINT OVERHAUL


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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



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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



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Fig. Fig. 9 Partially inserted bearing cap (top)



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Fig. Fig. 10 Installing the snaprings



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Fig. Fig. 11 Tapping the yoke in order to seat the retaining clip

Snapring (Cleveland) 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. If the snapring is difficult to remove, tap the end of the bearing cap lightly to relieve pressure from 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.  
  5. Place the universal joint so the lower ear of the yoke is supported on a 1 1 / 4 in. ID pipe or a 1 1 / 8 inch socket, depending on the application. 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 should be used for this.
  6.  
  7. Grasp the cap and work it out, if necessary use tool J-9522-5 or equivalent spacer to further push the the bearing cap from the trunnion, then grasp and work it free.
  8.  
  9. Rotate the shaft and support the other side of the yoke, then press the bearing cap from the yoke as in previous steps.
  10.  
  11. Remove the trunnion from the driveshaft yoke.
  12.  
  13. 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.
  14.  

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.  
  3. Partially insert the cross into the yoke so 1 trunnion seats freely in the bearing cup, then rotate the shaft so this trunnion is on the bottom.
  4.  
  5. Install the opposite bearing cap part way. Be sure both trunnions are started straight into the bearing caps.
  6.  
  7. 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 1 or more needles have not become lodged under an end of the trunnion.
  8.  
  9. As soon as 1 bearing retainer groove is exposed, stop pressing and install the bearing retainer snapring.
  10.  

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.  

Nylon Injected (Saginaw) 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 softjawed vise or blocks of wood to protect the yokes.

  1. Support the propeller shaft horizontally in line with the base plate of a bench vise, but never clamp the driveshaft tube.
  2.  
  3. Place the U-joint so the lower ear of the shaft yoke is supported by a 1 1 / 8 inch socket. Press the lower bearing cap out of the yoke ear. This will shear the nylon injected ring retaining the lower bearing cap.
  4.  
  5. If the bearing cup is not completely removed, lift the cross (J-9522-3) and insert J-9522-5 or equivalent spacer, then press the cap completely out.
  6.  
  7. Rotate the driveshaft, shear the opposite plastic retainer, and press the other bearing cup out in the same manner.
  8.  
  9. Remove the cross from the yoke.
  10.  

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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