There are noises coming from the front wheels of the car
Tire noise. Check if the tires are the correct size for the vehicle.
Loose fastening of the disk on the hub. Check the condition of the rim, wheel hub, wheel studs and nuts. Tighten fasteners or replace defective components.
The wheel is out of balance or the disc is bent. Balance the wheel or replace the disc.
The front hub bearings are faulty or their adjustment is broken. Correct the bearing preload or replace them.
Steering knuckle assembly bearings worn or damaged or out of adjustment. Check and replace bearings if necessary.
Worn or damaged CV joint (SHRUS) front wheel drive shaft. Check and replace the drive shaft if necessary.
Note. Jack up the front of the car and place it on jack stands. Check the tightness of the fixing nuts and the freedom of rotation of the wheels, measure the amount of wheel runout. Noises emitted by the front hub bearing appear as a rumble when one wheel is rotated separately. When checking the condition of the wheel bearings, the transmission must be in position "N", and the opposite wheel - to be blocked.
The noises emitted by CV joints are most noticeable while the car is moving with the steering wheel turned all the way. The state of the CV joint can be assessed by the metallic clicks emitted by the hub part of the wheel during its rotation back and forth. The transmission must be in first gear, the transfer case must be downshifted, and the disengageable hubs must be locked.
There are noises emitted by the main gear
Loose propeller shaft or worn cardan joint. Tighten fasteners or replace hinge.
Lubricant level dropped. Check for signs of oil leakage, if any, eliminate the cause. Add the correct grade of oil.
The nut of the final drive gear flange has loosened. Lubricate the nut with sealant and tighten to the required torque.
Worn or damaged final drive components. Perform a major overhaul of the final drive.
The pinion shaft rotates, but the front wheel does not
Disengageable hubs not engaged or defective. Check the proper functioning of the hubs with a disengageable drive, make the necessary repairs or replace.
Damaged drive shaft or CV joint. Check, replace shaft assembly.
Sheared castellated bolts (slave) main gear gears. Remove the final drive assembly and replace the bolts.
Damaged differential gears. Perform a major overhaul of the final drive.
Note. Remove the drive shafts and check their condition. If necessary, remove the final drive assembly and overhaul it. Follow the thoroughness of removing foreign particles and metal filings from the crankcase of the bridge.
Lubricant loss occurs
Main gear drive gear seal defective. Check (see accompanying illustration). Replace the gland, check the condition of the contact surface of the flange.
Defective drive shaft seal. Remove the drive shaft and replace the seal.
There is a leak at the final drive housing gasket. Remove the final drive assembly and replace the gasket.
Leakage occurs through pores or cracks in the final drive housing. Make any necessary repairs or replace the crankcase.
Note. Before cleaning the front axle assembly to check for signs of oil leaks, check the crankcase vent hose for blockage (see accompanying illustration). if leaks do not occur when the axle is cold, drive the vehicle with the axle warmed up to normal operating temperature, then carefully inspect the crankcase for signs of leaks through the smallest pores and cracks.