Bearing Preload Adjustment

It is not necessary to reestablish preload shim thickness when new bearings are installed. It is only necessary to establish preload shim thickness when a transaxle housing component, gear shaft, or differential is replaced. This procedure is used to measure zero end play of the gear shafts and differential in the C635 (Manual or DDCT) Transaxle and establish the proper thickness of the select shims placed behind the bearing races in the transaxle housing to apply specific bearing preload to prevent bearing failure and gear rattle.

Transaxle Preparation

1. Clean the transaxle with suitable solvent.
2. Install new bearings on the gear shafts and the differential.
   Fig 1: Removing Preload Bearing Races

   Courtesy of CHRYSLER GROUP, LLC
3. Remove the bearing races (2) from the transaxle housing using tools 9664 Remover (1) (special tool #9664, Remover, Bearing Cup) and C-637 Slide Hammer (special tool #C-637, Slide Hammer, Universal)

   .

4. Remove the factory installed select shims from the transaxle housing. Mark the shims to identify the bore that they were removed from.
5. From the circumference of the original bearing races, grind 0.18 mm (0.007 in) material from the races to allow them to slip-fit into the transaxle housing.
   NOTE:

   To ensure a flat uniform surface on the outside diameter (OD) of the bearing races, chuck them on a suitable (brake) lathe and remove material from the OD with a suitable die grinder.

6. Insert the, reduced OD, differential bearing race into the transaxle housing.
   NOTE:

   No select shim is required to measure the differential zero end play.

   Fig 2: Starter Shims & Plastigauge(R)

   Courtesy of CHRYSLER GROUP, LLC
7. Insert an 0.80 mm (0.031 in), or suitable thickness, starter shims (2) in each gear shaft bearing race bore in the transaxle housing. This will create measurable gear shaft end play after the transaxle cases are assembled.
   NOTE:

   If the original shims are greater than 1.32 mm (0.052 in) thick, use a 1 mm starter shim.

8. Use RED Plastigauge®, cut in 6 mm (1/4 in.) lengths (1), placed 120 degrees apart around the side surface of the select shims.
   NOTE:

   If the gear shaft end play is less than the RED Plastigauge® can accurately measure, use GREEN Plastigauge®.

9. Install the reduced diameter bearing races in the bores in the transaxle to capture the Plastigauge®.
   Fig 3: Differential Assembly In Bellhousing

   Courtesy of CHRYSLER GROUP, LLC
10. Install the differential assembly in the bellhousing half of the transaxle housing.
11. Place the bearing race plate in position on the bellhousing half of the transaxle housing.
12. Install the bolts to hold the bearing race plate to the bellhousing. Tighten the bolts to torque spec.
    Fig 4: Three Gear Shafts In Bellhousing

    Courtesy of CHRYSLER GROUP, LLC
13. Install the three gear shafts in the bellhousing half of the transaxle housing.
14. Install the transaxle housing onto the bellhousing.
    NOTE:

    If the reduced diameter bearing races slip out of the bearing bores, Door Ease® wax can be applied to the circumference of the race to adhere it to the bore.

    Fig 5: Transaxle Housing To Bellhousing Bolts

    Courtesy of CHRYSLER GROUP, LLC
15. Install four bolts (1) to hold the transaxle housing to the bellhousing around the differential side of the transaxle. Tighten the bolts to 50% of the torque specification.
16. Turn the transaxle on its side to gain access to the inside of the bellhousing.
17. Install seven bolts (2), four above and three below the gear shafts, to hold the transaxle case halves together, Tighten the bolts to 50% of the torque specification.
18. Turn transaxle, bellhousing downward, on the work surface.

Measuring Differential End Play

1. Install (special tool #C-4995A, Tool, Differential Bearing Torque) (1) into the differential side gear (2).
   Fig 6: Installing Special Tool To Differential Side Gear

   Courtesy of CHRYSLER GROUP, LLC
2. Clamp a typical vise grip pliers (4) on tool C-4995A (2).
3. Attach dial indicator C-3339A (1) (special tool #C-3339A, Set, Dial Indicator) to transaxle housing with the plunger placed on the end of tool C-4995A (2).
   Fig 7: Measuring Differential End Play

   Courtesy of CHRYSLER GROUP, LLC
4. Zero the indicator dial (1).
5. Use a large screw driver (3) to pry upward on tool C-4995A (2) to take up the bearing free play.
6. While holding tool C-4995A (2) upward read the dial indicator (1).
7. Add 0.15 mm (0.006 in.) to the dial indicator reading.
8. The sum is the proper thickness of the differential preload shim.

Measuring Gear Shaft End Play

1. Turn the transaxle on its side to gain access to the inside of the bellhousing.
   Fig 8: Transaxle Housing To Bellhousing Bolts

   Courtesy of CHRYSLER GROUP, LLC
2. Remove the bolts (2) holding the bellhousing to the transaxle housing.
3. Turn transaxle, bellhousing downward, on the work surface.
4. Remove the remaining bolts (1) holding the bellhousing to the transaxle housing.
5. Place the transaxle housing on the work surface inside up.
   Fig 9: Bearing Race, Shim & Plastigauge(R)

   Courtesy of CHRYSLER GROUP, LLC
6. Using a hook tool, remove the reduced size bearing races (4). Be careful not to damage the Plastigauge® (2).
7. Compare the thickness of the Plastigauge® (2) to the RANGE template on the Plastigauge® packaging (1).
8. Add the Plastigauge® RANGE thickness, plus 0.15 mm (0.006 in.) to the thickness of the starter shim used to create gear shaft end play.
9. The sum is the proper thickness to preload for each of the gear shaft bearings.
10. Install the closest thickness shims from the list provided by Mopar® Parts.
    NOTE:

    If the measured thickness falls between the shim thicknesses provided by Mopar® Parts, install the shim that is slightly thicker.

After proper bearing preload is established, finish assembling the transaxle.