Transfer case BMW X5 2000 E53 Workshop Manual

2
Introduction
The X5 marks BMW’s introduction into the luxury “Sports Activity Vehicle (SAV)” niche seg-
ment of the Sport Utility Vehicle market. While carrying the designation X5, the vehicle is not
based on the 5 Series but it is its own new car-like platform. The X5 is offered with two
engine variants:
• The 4.4 liter M62 TU engine equipped with the A5S 440 Z automatic transmission.
• The 3 liter M54 engine with either the GM 5 automatic or 5 speed manual transmission
The X5 incorporates the following
features:
• Four wheel independent sus-
pension (BMW tradition)
• Full time - all wheel drive
(planetary gear transfer case)
• All road vehicle (ON/OFF road
capabilities)
• High ground clearance
• Unitized body and Chassis
(car like ride and handling)
• Double pivot front suspension
• “Integral Link” rear suspen-
sion with air spring self level-
ing
• X5 specific traction control
system
Two different suspension options are offered (standard and sport) with different springs,
shock absorbers and stabilizers.
The X5 has 180 mm ground clearance, for both suspensions to allow off road travel.
However, the suspension travel is the same as the E39 which allows the X5 to retain a car
like feel when driven every day.
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Drivetrain
The transfer case, driveshafts, final drives and half shafts make up the drivetrain assembly.
The transfer case is always mounted in the same position on the X5. This applies to other
markets and future models that will utilize different transmissions for different engine con-
figurations. With these models, the transmission tail shafts will be modified to match up with
the transfer case.
The rear driveshaft is a two piece unit using a center bearing, while the front drive shaft is
a single piece that is splined to the transfer case and bolted to the front differential.
The breather vents for both differentials and the transfer case are mounted higher up on the
chassis to prevent water from entering if the vehicle is driven off road through water. The
front breather passes up into the engine compartment and is mounted under the left side
ignition coil cover. The rear breather passes along the under side of the body and is mount-
ed behind the left side wheel arch cover. The breather vent for the transfer case is mount-
ed up high in the driveshaft tunnel.
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Drivetrain-Transfer Case
The transfer case is manufactured by New Process Gear Division of New Venture Gear
Company. It is identified as model NV 125.
It incorporates a planetary gear set and chain to provide the torque split and all wheel drive.
The output torque of the transmission is applied to the planetary carrier of the gear set. The
rear drive shaft is connected to the annulus gear and the front drive shaft is connected to
the sun gear through the chain drive.
As the output shaft of the transmission turns, the planetary carrier rotates, causing the
planetary gears to drive the sun gear and annulus gear.
A torque split of 68% rear/ 32% front is provided through the gearing of the planetary set.
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