Volkswagen Cars 2000-05

Transaxle Overhaul

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Gear Case, Input Shaft & Pinion Shaft



Assembly
  1. If the transaxle case, ring gear or the side bearings are replaced, adjust differential side bearing pre-load before assembling the transaxle.
  2.  
  3. If none of these items is being replaced, go to Step 6. If new bearings are being installed, heat the bearing to about 212°F (100°C) and press it onto the shaft until it is fully seated. Be sure to replace the race in the housing.
  4.  
  5. Install a 0.65mm (0.025 inch) shim into the housing and temporarily install the bearing outer race. If this shim is not on hand, a thicker shim may be used but it must be small enough to allow some pinion shaft end play.
  6.  
  7. Set the pinion shaft into place. Do not oil the bearings or turn the shaft. Fit the outer race onto the smaller bearing, install the bearing plate and tighten the bolts to 30 ft. lbs. (40 Nm).
  8.  
  9. Attach a dial indicator to the case and measure the end play of the shaft. Be careful not to turn the shaft or the bearings will settle and cause an incorrect reading.
  10.  
  11. The correct bearing shim size is obtained by adding the end-play measurement, the starting shim and a bearing pre-load of 0.20mm (0.008 inches). For example:

    Starting shim: 0.65mm (0.025 inches)
     
    End play: 0.30mm (0.012 inches)
     
    Pre-load: 0.20mm (0.008 inches)
     
    Correct shim: 1.15mm (0.045 inches)
     

  12.  
  13. Shims are available in sizes from 0.65mm-1.40mm (0.025-0.055 in). Install the correct shim and oil the bearings before installing the pinion shaft.
  14.  
  15. Install the bearing plate and tighten the bolts to 30 ft. lbs. (40 Nm). When the bearing pre-load is correct, it should require 5-13 inch lbs. to turn the shaft with new bearings or at least 3 inch lbs. with used bearings.
  16.  
  17. Install the 1st gear thrust washer with the shoulder facing the bearing plate.
  18.  
  19. If the synchronizer was disassembled:

    The original first gear synchronizer ring has a space with 3 teeth missing. The replacement ring has a full set of teeth and dimension a will be 0.042-0.066 inches (1.1-1.7mm).
     
    When assembling the 1st/2nd gear synchronizer, the groove in the hub must face first gear. The groove may be on the face or the edge of the teeth.
     
    The bent tab on the end of the key retainer spring must fit into one of the keys.
     

  20.  
  21. Install the needle bearing. The sychronizer hub should be heated to about 250°F (120°C) and must be pressed onto the shaft. Align the synchro ring grooves with the keys.
  22.  
  23. Install the reverse gear shaft and the gear.
  24.  
  25. If the 2nd gear needle bearing was removed, the race must be pressed or driven onto the shaft. Install the bearing, synchronizer assembly and 2nd and 3rd gears.
  26.  
  27. Install the 3rd gear circlip and make sure there is no gear end play. If the gear moves on the shaft or if the circlip cannot be installed, there are circlips available in thickness from 0.098-0.118 inches (2.5-3.0mm).
  28.  
  29. When assembling the input shaft, the new third gear synchronizer ring dimension A is 0.045-0.068 inches (1.15-1.75mm). The groove in the outer teeth must be towards fourth gear, the chamfer on the splines must be towards third gear.
  30.  
  31. If the input shaft has not been disassembled, remove the ball bearing with a puller that contacts only the inner race.
  32.  
  33. Install the input shaft assembly.
  34.  
  35. Install 4th gear and the circlip onto the pinion shaft.
  36.  
  37. Install the original ball bearing shim and press the bearing into the case. The wide shoulder on the inner race faces 4th gear.
  38.  
  39. Install the bearing retainer plate. Apply a thread locking compound to the bolts and tighten them to 11 ft. lbs. (15 Nm).
  40.  
  41. Install the shift fork assembly.
  42.  
  43. Temporarily install the bolt into the reverse gear shaft. Turn the shaft so the bolt is evenly spaced between the case bolt holes, then remove the bolt.
  44.  
  45. Install a new gasket or apply a silicone sealer to the gear carrier.
  46.  
  47. Make sure the input shaft is supported at the bell housing. Slip the case onto the carrier and carefully drive the inner race of the ball bearing onto the input shaft.
  48.  
  49. Install a new gasket and start the bolt into the reverse gear shaft.
  50.  
  51. Install the case bolts and tighten them to 18 ft. lbs. (25 Nm). Tighten the reverse shaft bolt to 18 ft. lbs. (25 Nm).
  52.  
  53. Install the drive flange with a new circlip.
  54.  
  55. Heat 5th gear to about 212°F (100°C) and install it onto the shaft. Install the thrust washer and circlip.
  56.  
  57. Fit the sychronizer assembly onto the shaft and thread the tube up through the fork. The tube should project 0.197 inches (5.0mm) above the fork. Don't install the locking plate yet.
  58.  
  59. Turn the input shaft at the input end and operate the shift forks to make sure the gears engage. DO NOT remove the shift rod from the tube or the fork assembly will fall apart inside the transaxle.
  60.  
  61. Shift the transaxle into 5th and reverse at the same time to lock it.
  62.  
  63. Apply a thread locking compound to a new synchronizer hub bolt, install the bolt and tighten it to 111 ft. lbs. (150 Nm).
  64.  
  65. Install the selector shaft assembly, spring and cap. Tighten the cap to 37 ft. lbs. (50 Nm).
  66.  
  67. Turn the input shaft while moving the selector shaft in and out, left and right to check engagement of all the gears.
  68.  
  69. Before installing the shift tube locking plate, check the gear alignment:

    Pull the selector shaft out and turn to the left to select 5th gear.
     
    Lift slightly on the shift fork to take up any free play in the sleeve.
     
    Measure the overlap of the sleeve on 5th gear. The sleeve must be 0.039 inches (1.0mm) down over the gear. Adjust the sleeve position with the selector tube.
     

  70.  
  71. Slip 2 wrenches under the fork and press a new locking plate onto the tube.
  72.  
  73. Install the clutch pushrod.
  74.  
  75. Use a new gasket and install the end cover. Tighten the bolts to 18 ft. lbs. (25 Nm).
  76.  

Disassembly


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Fig. View of a synchronizer blocking ring and gear assembly



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Fig. Inspect all gears for chipped teeth



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Fig. Synchronizer sleeve engaged with third gear


NOTE
The 5th gear synchronizer bolt and all circlips should be replaced any time they are removed. The 3rd gear circlip is used to adjust end play and comes in different thickness. The input shaft used with 8 valve engines is different from 16 valve engines and they cannot be interchanged.

  1. Mount the transaxle assembly in a holding fixture.
  2.  
  3. Mount a bar with a bolt and spacer across the bellhousing to support the mainshaft.
  4.  
  5. Remove the cap from the drive flange and discard it.
  6.  
  7. The left drive flange must be removed to disassemble the case. If the differential is to be removed, both drive flanges must be removed. There is a strong spring pushing the drive flange out against the circlip. If the special removal tool is not available:

    Locate a heavy bar that fits across the flange but leaves room around the side to access the circlip. Drill a 0.470 inch (12mm) hole through the center.
     
    Locate a long bolt or threaded rod that fits the M10 threads in the center of the output shaft.
     
    Use the bar and bolt to draw the flange down against the spring just enough to unload the circlip.
     
    Remove the circlip, then remove the bolt to remove the output flange.
     

  8.  


NOTE
The left and right drive flanges are different. Label them for proper assembly and keep them together with the tapered rings.

  1. Remove the end cover and gasket. DO NOT remove the selector rod that has the small spring on the end. The selector assembly will fall apart inside the transaxle.
  2.  
  3. Remove the back-up light switch.
  4.  
  5. Remove the selector shaft detent plungers. Remove the cover, spring and selector shaft.
  6.  
  7. Use a screwdriver to move both front selector forks to engage 5th and reverse at the same time. This will lock the gear train so it cannot turn.
  8.  
  9. Remove the bolt from the center of the 5th gear synchro assembly. The bolt is very tight and is held in with thread locking compound. Make sure the transaxle is securely supported.
  10.  
  11. Pry the locking plate up and remove it. Unscrew the selector tube to remove the shift fork and synchro as an assembly. The tube does not move up or down, the shift fork will move up the tube. Be careful not to remove the selector rod.
  12.  
  13. Remove the circlip from 5th gear. On the 16 valve engine, 5th gear is secured with a plate. It may be necessary to use a puller to remove 5th gear.
  14.  
  15. Remove the reverse shaft fixing bolt from the side of the case.
  16.  
  17. Use an M6 12 point socket to remove the 4 bolts holding the input shaft bearing retainer to the rear of the case.
  18.  
  19. Remove the bolts holding the case halves together.
  20.  
  21. Secure a puller to the rear cover bolt holes so the bolt contacts the input shaft. Carefully press the housing off the rear bearing and lift the housing away from the transaxle. There may be a shim on top of the bearing.
  22.  
  23. To remove the shift forks, lift the selector rod slightly and remove the shift forks as an assembly.
  24.  
  25. To remove the input shaft, remove the 4th gear circlip. Lift out 4th gear and the input shaft together.
  26.  
  27. To remove the pinion shaft, the gears must be removed first. Remove the 3rd gear circlip and lift 3rd gear, 2nd gear, the bearings and the synchro assembly off the shaft. Be sure to place them on the bench in order, facing the same way, to ease correct assembly.
  28.  
  29. Remove the reverse gear and shaft.
  30.  
  31. Use a puller to remove the 1st gear and the 1st/2nd synchro together.
  32.  
  33. Remove the bolts to remove the bearing plate and the pinion shaft.
  34.  
  35. Third and 4th gear synchronizer must be pressed off the pinion shaft.
  36.  
  37. Before disassembling the synchronizers, measure the wear at dimension a with a feeler gauge. If the gap is 0.020 inches (0.5mm) or less, the synchronizer ring must be replaced.
  38.  
  39. The bearings can be removed from the shafts and the case with the appropriate pullers. If bearings are removed, they should be replaced. Pay attention to any shims or spacers and make sure they are labeled for correct installation.
  40.  

 
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