BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Transfer Case Assembly

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REMOVAL & INSTALLATION



With Manual Transmission

To perform this procedure, a special, large wrench that locks onto flats on alternate sides of a section of the rear driveshaft is required. Use tool 26 1 060 or an equivalent.

  1. Disconnect the negative battery cable. Raise and safely support the vehicle. Remove the exhaust system. Unbolt and remove the exhaust system heat shields located behind and below the transfer case.
  2.  
  3. Unscrew the rear section of the driveshaft at the sliding joint located behind the output flange of the transfer case.
  4.  
  5. Hold the through-bolts stationary and remove the self-locking nuts from in front of the flexible coupling at the transfer case output flange. Discard all the self-locking nuts and replace them.
  6.  

During the next step, be careful not to let the driveshaft rest on the metal fuel line that crosses under it or the line could be damaged.

  1. Slide the sections of the driveshaft together at the sliding joint and then pull the front of the driveshaft off the centering pin at the transmission output shaft.
  2.  
  3. Remove the nuts and through bolts from the flexible coupling linking the transmission output flange with the short driveshaft linking the transmission and the transfer case.
  4.  
  5. Support the transmission from underneath in a secure manner. Then, mark each of the 4 bolts fastening the crossmember that supports the transmission at the rear to the body, bolts are of different lengths. Remove the crossmember.
  6.  
  7. Lower the transmission/transfer case unit just enough to gain access to the bolts linking the 2 boxes together. Remove the 2 lower and 2 upper bolts. It is possible to gain access to the upper bolts using a socket wrench with a U-joint and extension.
  8.  
  9. There is a protective cap on the forward driveshaft where it links up with the transfer case. The cap is made of a brittle material, so it must be handled carefully. Gently slide the cap forward until is free of the transfer case.
  10.  
  11. Slide the transfer case to the rear so it can be separated from both the transmission and the forward driveshaft. When it is free, remove it.
  12.  

To install:
  1. Install the transfer case under the vehicle and raise it into position, bearing the following points in mind:
    1. Inspect the dowel holes locating the transfer case with the transmission and the guide hole for the output shaft where it slides into the transfer case to make sure these parts will be properly located. Lubricate the guide pin and the splines of the front driveshaft section with grease.
    2.  
    3. When fitting the transfer case onto the transmission, check to make sure the output flange of the transmission is properly aligned with the flexible coupling. Put the through-bolts through the flexible coupling and then install and torque the nuts to 65 ft. lbs. (88 Nm) while holding the bolts stationary, rather than turning them.
    4.  
    5. When reconnecting the transfer case to the gearbox, torque the bolts to 30 ft. lbs. (41 Nm).
    6.  
    7. Before fitting the driveshaft back onto the rear of the transmission, retain the seal in the protective cap by applying grease to it.
    8.  
    9. Torque the transmission crossmember bolts to 17 ft. lbs. (23 Nm).
    10.  
    11. Check the fluid level and fill with the recommended lubricant.
    12.  

  2.  

With Automatic Transmission

To perform this procedure, a special, large wrench that locks onto flats on alternate sides of a section of the rear driveshaft is required. Use tool 26 1 060 or an equivalent.

  1. Disconnect the negative battery cable. Raise and safely support the vehicle. Remove the exhaust system. Unbolt and remove the exhaust system heat shields located behind and below the transfer case.
  2.  
  3. Unscrew the rear section of the driveshaft at the sliding joint located behind the output flange of the transfer case.
  4.  
  5. Hold the through-bolts stationary and remove the self-locking nuts from in front of the flexible coupling at the transfer case output flange. Discard all the self-locking nuts and replace them.
  6.  

During the next step, be careful not to let the driveshaft rest on the metal fuel line that crosses under it or the line could be damaged.

  1. Slide the sections of the driveshaft together at the sliding joint and then pull the front of the driveshaft off the centering pin at the transmission output shaft.
  2.  
  3. Remove the nuts and through bolts from the flexible coupling linking the transmission output flange with the short driveshaft linking the transmission and the transfer case.
  4.  
  5. Note the locations of all the washers and then loosen the retaining nut and disconnect the range selector lever cable at the transmission by pulling out the pin. Be careful not to bend the cable in doing this. Then, loosen the nuts that position the cable housing onto the transmission and slide the cable housing backward so it can be separated from the bracket on the transmission housing.
  6.  
  7. There is a protective cap on the forward driveshaft where it links up with the transfer case. The cap is made of a brittle material, so it must be handled carefully. Gently slide the cap forward until is free of the transfer case.
  8.  
  9. Remove the drain plug in the bottom of the pan and drain the transmission fluid.
  10.  
  11. Support the transmission from underneath in a secure manner. Then, mark each of the 4 bolts fastening the crossmember that supports the transmission at the rear to the body, bolts are of different lengths. Remove the crossmember.
  12.  
  13. Remove the 9 nuts fastening the transfer case to the transmission housing. Note the location of the wiring holder so it will be possible to reinstall it on the same bolt.
  14.  
  15. Slide the transfer case to the rear and off the transmission.
  16.  

To install:
  1. Install the transfer case under the vehicle and raise it into position, bearing the following points in mind:
    1. Inspect the sealing surfaces as well as the dowel holes in the transfer case to make sure they will seal and locate properly. Clean the sealing surfaces and replace the gasket.
    2.  
    3. When sliding the transfer case back onto the transmission, turn the front driveshaft section slightly to help make the splines mesh.
    4.  
    5. When reconnecting the shift cable, inspect the rubber mounts and replace any that are cut, crushed, or cracked. Adjust the shift cable.
    6.  
    7. Before fitting the driveshaft back onto the rear of the transmission, retain the seal in the protective cap by applying grease to it.
    8.  
    9. When fitting the transfer case onto the transmission, check to make sure the output flange of the transmission is properly aligned with the flexible coupling. Put the through-bolts through the flexible coupling and then install and torque the nuts to 65 ft. lbs. (88 Nm) while holding the bolts stationary, rather than turning them.
    10.  
    11. Torque the bolts holding the transfer case to the transmission to 65 ft. lbs. (88 Nm).
    12.  
    13. Torque the transmission crossmember bolts to 17 ft. lbs. (23 Nm).
    14.  
    15. Check the fluid level and fill with the recommended lubricant.
    16.  

  2.  

 
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