The front wheel driveshafts with constant velocity joints (CV joints) serve to transmit torque from the final drive, installed in the gearbox, to the driving front wheels at various wheel steering angles and suspension travels.
The right and left front wheel driveshafts are not interchangeable.
The wheel driveshaft consists of an inner and an outer constant velocity joint, connected to each other by a shaft.
The driveshaft is made from a forged steel bar.
Splines are made at the ends of the shaft, on which the CV joints are mounted.
The outer and inner joints of the driveshafts have different designs.
The outer joint of the driveshaft enables torque transmission at various steering angles of the driving wheels.
The outer joint consists of a housing, a separator, a cage and eight balls, which are placed in profiled grooves of the housing and the cage.
The separator constantly holds the balls in the bisector plane between the housing and the cage of the joint and ensures uniform transmission of rotation from the cage to the housing.
The joint cage is mounted on the splines of the shaft and secured against longitudinal movement by a retaining ring.
The splined shank of the outer joint housing, at the end of which a thread is cut, is inserted into the front wheel hub and, when the nut is tightened, pulls together the inner rings of the bearing.
The outer joints of the right and left front wheel driveshafts are interchangeable.
The inner joint of the driveshaft enables angular movements of the suspension and compensates for the mutual movements of the suspension and the power unit by changing the length of the driveshaft.
The inner joints of the right and left wheel driveshafts on the 4х4 vehicle are not interchangeable due to the different design of their housings.
On the splined end of the driveshaft on the inner joint side, a hub with three pins is mounted — the tripod, on each of whose pins (journals) a bearing is located, whose outer ring has a spherical surface.
The inner ring of the bearing is mounted on the pin with a clearance and has the possibility of significant axial movement along the pin.
As a result of the operation of the front suspension, the bearings move in three longitudinal grooves of the joint housing.
At the same time, the tripod pins can occupy various positions relative to the bearings.
Each end of the pin is compressed, as a result of which the bearing cannot be removed from the pin, so the assembly becomes non-detachable.
The spring installed inside the inner joint housing ensures constant pressing of the joint housing against the differential half-shaft gear.
The splined connection of the shank of the inner joint housing of the left wheel driveshaft is secured in the differential half-shaft gear by a retaining ring.
The splined hub of the joint housing of the right wheel driveshaft is fitted with a tight fit onto the splines of the idler shaft of the transfer gearbox.
The sealing of the joints is an indispensable condition for their reliable operation.
The sealing of the outer and inner joints is ensured by mud-protective boots, secured on the shaft and the housing by single-use metal clamps.
Before assembly, a special grease for wheel driveshaft joints is placed in the outer and inner joints.
Topping up or replacing the grease, as well as any other maintenance of the wheel driveshafts during vehicle operation, is not required.
It is only necessary to monitor the condition of the protective boots of the joints and the securing of their clamps.
Distinctive features of the front wheel driveshafts of the 4х2 vehicle
On the 4х2 vehicle, the inner joint housing of the right wheel driveshaft rests on an intermediate support, which also holds the joint housing against axial displacement.
The support bearing of the intermediate support, pressed onto the shank of the joint housing, is installed in the bracket of the engine cylinder block and closed by a cover.
The cover is installed on the axis of the bracket and secured to it by a bolt.
The splined end of the shank of the inner joint housing of the left wheel driveshaft is inserted into the opening of the differential half-shaft gear.
On the 4х2 vehicle, the outer joints of the driveshafts are interchangeable, and the inner ones — not interchangeable.
The operations for repairing the front wheel driveshafts of the 4х2 vehicle are the same as the corresponding operations of the driveshafts of the 4х4 vehicle.
Possible front wheel driveshaft faults
Cause (Remedy)
Vibration when the vehicle is moving:
- Severe wear of the outer joint of the wheel driveshaft — replace the worn joint;
- Deformation of the wheel driveshaft — replace the wheel driveshaft;
- Wear of the rollers of the inner joint of the wheel driveshaft — replace the inner joint;
- Loosening of the hub securing nut — tighten or replace the nut.
Vehicle pulling to one side:
- Wear or damage to the cage of the inner joint — replace the joint;
- Wear or damage to the outer joint — replace the joint;
- Damage or deformation of the wheel driveshaft — replace the shaft;
- Loosening of the tightening of the hub securing nut — tighten or replace the nut.
Grease leakage from the joint:
- Wear or rupture of the protective boot of the outer or inner joint — inspect the joint, if there is play, replace the damaged boot and grease;
- Insufficient tightening of the clamps — replace and firmly tighten the clamps.
Noise, knocking from the front wheel side when the vehicle is moving:
- Damage or deformation of the wheel driveshaft — replace the shaft;
- Run-out of the front wheel driveshaft — replace the shaft;
- Damage to the bearing of the intermediate support of the right front wheel driveshaft of a front-wheel drive vehicle — replace the bearing or the driveshaft assembly;
- Wear of the rollers of the inner joint of the wheel driveshaft — replace the inner joint;
- Loosening of the hub securing nut — tighten or replace the nut.
Knocking when the vehicle turns:
- Severe wear of the outer joint of the wheel driveshaft — replace the joint.
