of 4WD vehicles can be serviced in basically the same manner as the identical
components of a 2WD vehicle. Before doing any servicing, however, it is
necessary to give the undercar a complete inspection. Pay particular attention
to the steering dampers, steering linkage, wheel bearing, ball joints, coil
springs, and radius arm bushings.
U-joints, slip joints, or CV joints on a 4WD drivetrain that must be lubed on a
regular basis. To service the drive shafts on a four-wheel-drive vehicle, use
the general instructions given earlier for a cross universal joint. A four-wheel
drive simple uses two drive shafts instead of one.
Servicing the Transfer Case
all automobile servicing procedures, be sure to check the manufacturer's service
manual for specific transfer case repair and overhaul procedures. It gives
details for the particular make and model of transfer case to be worked on.
removing the transfer case, disconnect and remove all driveline or propeller
shaft assemblies. Be sure to mark the parts and their relative positions on
their yokes so the proper driveline balance can be maintained when reassembled.
Disconnect the linkage to the transfer case shift lever. Also disconnect wires
to switches for 4WD dash indicator lights, if used. Remove all fasteners holding
the case and move it away from the transaxle or transmission.
transfer case has been removed from the vehicle and safely supported, take off
the case cover and disconnect any electrical connections. Visually inspect for
any oil leaks. Then carefully loosen and drive out the pins that hold the shift
forks in place. Remove the front output shafts and chain drive or gearsets from
the case. Keep in mind that some cases use chain drives while others use spur or
helical cut gearsets to transfer torque from the transaxle or transmission to
the output shafts. Planetary gearsets provide the necessary gear reductions in
some transfer case.
carefully inspect all parts for damage and wear. Check the slack in the chain
drive by following the procedure given in the service manual. Replace any
defective parts. It may be necessary to measure the shaft assembly end play. If
excessive, new snap rings and shims may be used to correct the situation.
reassembling the transfer case, the procedure is essentially the reverse of the
removal. Be sure to use new gaskets between the covers when reassembling the
It is very
important to bear in mind that the fluid level in a transfer case must be
checked at recommended time intervals. The lubricant should be almost even with
the fill hole. Always refer to the service manual for recommended transfer case
lubricants. Many transfer cases require extreme pressure (EP) lubricants as used
in differentials and in some manual transmissions.