The VAZ-2123 transfer case is designed to change the torque value and distribute it between the front and rear axles.
The transfer case has two gears with gear ratios of 1.20 and 2.135.
The parts of the transfer case are cast from aluminum alloy and connected to each other with studs and nuts. The upper part of the crankcase has a hatch covered with a stamped steel cover.
The front cover is centered on the crankcase by two mounting pins.
There are cardboard gaskets between the covers and the crankcase (a sealant - gasket can be used instead of them during repairs).
All shafts are sealed with rubber-metal cuffs (oil seals).
The speed sensor drive shaft, gear shift fork rods and differential lock are sealed with rubber rings.
There are two holes in the front cover - a filler (also a control one) and a drain hole.
Transfer case with drive: 1 - differential lock clutch fork; 2 - differential lock fork rod; 3 - rod protective cover; 4 - lock washer; 5 - lever axis bushing; 6 - lever axis; 7 - differential lock lever; 8 - fork lock bolt; 9 - differential lock indicator lamp switch; 10 - gear shift fork rod; 11 - differential lock lever rod; 12 - control lever bracket fork; 13 - control lever; 14 - gear shift clutch fork; 15 - spacer sleeve; 16 - spring and retainer ball; 17 - retainer spring bushing; 13 - drive shaft flange; 19 - front cover; 20 - drive shaft oil seal; 21 - bearing thrust ring; 22 - drive shaft front bearing; 23 - high gear pinion; 24 - gearshift clutch; 25 - transfer case housing; 26 - low gear pinion; 27 - drive shaft rear bearing; 23 - drive shaft rear bearing mounting ring; 29 - drive shaft; 30 - bushing; 31 - hub; 32 - rear cover; 33 - intermediate shaft rear bearing; 34 - intermediate shaft; 35 - differential rear bearing; 36 - rear axle drive shaft bearing; 37 - flange; 33 - rear axle drive shaft oil seal; 39 - differential rear housing; 40 - pinion thrust washer; 41 - rear axle drive pinion; 42 - satellite shaft; 43 - retaining ring; 44 spring washer; 45 - suspension side bracket; 46 - satellite thrust washer; 47 - front axle drive housing; 48 - satellite; 49 - differential driven pinion; 50 - differential front housing; 51 - retaining ring; 52 - spring washer; 53 - differential housing front bearing; 54 - differential lock clutch; 55 - differential front bearing mounting ring; 56 - oil deflector; 57 - front axle drive shaft oil seal; 58 - front axle drive shaft bearing; 59 - front axle drive shaft; 60 - front axle drive shaft flange; 61 - oil drain plug; 62 - driven gear of speed sensor drive; 63 - intermediate shaft roller bearing; 64 - leading gear of speed sensor drive; 65 - filler plug
The drive shaft is mounted on two ball bearings, the outer rings of which are located in the seats of the front cover and crankcase.
The inner ring of the front bearing is clamped between the shaft flange and the thrust ring of the self-locking nut of the shaft flange.
The inner ring of the rear bearing is clamped between the shaft flange and the thrust washer located under the nut of the rear end of the shaft.
The nut is locked by pressing its edge into the grooves on the shaft.
The drive shaft is fixed from axial displacement by a mounting ring in a groove on the outer ring of the rear bearing, clamped between the crankcase and the rear cover. There are two drive gears on the drive shaft.
The front (large) one is the highest gear, it rotates freely on the heat-treated shaft journal.
The rear (smaller) one is the lowest gear, it rotates freely on the heat-treated sleeve, mounted on the shaft with tension.
The gears have two rims.
The helical (large) rims are in constant engagement with the corresponding gears of the intermediate shaft, and the gear shift clutch is connected to the straight-toothed (small) rims when the gear is engaged.
The clutch moves along the hub, which is rigidly mounted on the splines of the shaft between the drive gears.
In the middle position of the clutch, both gears are disengaged ("neutral") and the torque from the engine is not transmitted to the wheels.
The intermediate shaft is a block of two helical gears that are in constant engagement with the gears of the drive shaft.
The front gear is also in engagement with the driven gear, which is fixed to the differential housing entsiala.
The intermediate shaft rotates in two bearings: the front one is a roller bearing, the rear one is a ball bearing.
The shaft is secured against axial displacement by a mounting ring in the groove of the outer ring of the rear bearing, which is clamped between the crankcase and the rear cover (the same as the drive shaft).
A steel drive gear of the speed sensor drive is pressed into the front end of the shaft.
The driven gear is plastic, mounted on a shaft rotating in the sleeve of the speed sensor drive housing.
The housing is secured to the front cover of the transfer case.
View of the rear side of the transfer case: 1 - left suspension bracket; 2 - cross member of the rear suspension bracket; 3 - rear propeller shaft; 4 - rear cover of the transfer case; 5 - front propeller shaft
The front end of the front axle drive shaft rests on a ball bearing in the front axle drive housing.
The front axle drive housing is secured to the front cover of the transfer case.
The inner ring of the bearing is clamped between the shaft flange and the thrust ring of the self-locking nut of the shaft flange.
The bearing is secured against axial displacement by a retaining ring that fits into the groove of the front axle drive housing.
The rear splined end of the shaft is connected to the front axle drive gear of the differential.
The spur gear on the shaft serves to lock the differential.
The design and installation of the rear axle drive shaft is similar, but on it has no gear.
The differential housing is split, its two parts are connected with six bolts.
The same bolts also secure the driven gear to the differential housing.
The differential housing is mounted on two ball bearings.
The inner ring of the front bearing is held from displacement by a spacer spring washer resting on a retaining ring in the groove of the differential housing.
A mounting ring, clamped between the front cover of the transfer case and the front axle drive housing, fits into the groove on the outer ring of the bearing.
Thus, the differential housing is held from axial displacement by the front bearing; the rear bearing is not fixed.
The front part of the differential housing has splines along which the locking clutch moves.
When the lock is engaged, the clutch connects to the gear on the front axle drive shaft, connecting it to the differential housing.
View of the front side of the transfer case: 1 - right suspension bracket; 2 - filler plug; 3 - intermediate shaft; 4 - speed sensor; 5 - speed sensor drive housing, 6 - front propeller shaft; 7 - front axle drive housing cover; 8 - left suspension bracket; 9 - rear propeller shaft; 10 - transfer case front cover, 11 - transfer case housing; 12 - drain plug
The differential housing holes accommodate the satellite axle, held in place by two retaining rings.
There is a spring washer under one of the rings, preventing axial movement of the satellite axle.
The satellites (bevel gears) located on the axle are in constant engagement with the axle drive gears.
Thrust washers are installed between the differential housing and the satellites.
Their thickness is selected so that the axial clearance of the axle drive gears does not exceed 0.10 mm, and the torque of resistance to rotation is 14.7 Nm.
The transfer case is controlled manually, with a mechanical lever drive.
The driver shifts gears and engages the differential lock with one lever.
The lower end of the lever is connected to the gear shift rod, and through a rod connected to the lever axis, to the differential lock rod.
The other end of each rod is connected to the fork of the corresponding clutch (gear shift or differential lock), and this connection is locked with a bolt.
Each rod is sealed and protected from dust by a rubber corrugated cover at the exit from the box.
A ball lock is used to fix the drive in the selected position - a spring-loaded ball enters the grooves on the rods.
There are three of them on the gear shift rod - for "neutral", high and low gears, on the differential lock rod - two ("on" and "off").
In the front drive cover bridge has a switch screwed in that closes the control lamp circuit when the differential lock is engaged.
Possible faults transfer case VAZ-2123
Vibration of the transfer case and the body floor (in the area of the front seats) in all driving modes:
- Failure of the flexible coupling of the intermediate shaft - Replace the flexible coupling
Vibration of the transfer case and the body floor (in the area of the front seats) when starting the car and accelerating to 80 km / h;
- The transfer case supports and the rear support of the power unit are not tightened or are damaged - Tighten the nuts and bolt securing the supports, replace the damaged supports
- Tight turning or jamming in one of the planes of the hinges of the front or rear cardan shafts - Repair the cardan joints or replace the hinges in assembly
- Incomplete release of the parking brake - Adjust the parking brake drive
- Difficult to turn the constant velocity joint of the intermediate shaft - Check the condition of the boot and joint. If the joint parts are worn or damaged, replace the joint assembly
Vibration of the transfer case and the body floor (in the area of the front seats) during steady-state driving (most typical at a speed of 80-90 km/h):
- Increased imbalance of the driveshafts - Repair or replace the driveshafts
- Increased imbalance of the transfer case center differential - Replace the center differential
- Joining of the front or rear driveshaft cardan joints - Repair the joints or replace the driveshafts as an assembly
- Joining of the constant velocity joint of the intermediate shaft - Check the condition of the boot and joint. If the parts are damaged, the joint must be replaced
- Loose nuts and bolts for fastening the engine mounts or damaged engine mounts - Tighten the nuts and bolts for fastening the mounts or replace the mounts
- Bent bolts and flange of the flexible coupling of the intermediate shaft - Replace the bolts or the intermediate cardan shaft
Difficult gear shifting or differential locking:
- Seizing of the couplings on the splines of the hub, differential housing, front axle drive shafts - Clean off burrs, nicks or scuffs, replace damaged parts
- Nicks on the teeth of the small ring gear of the high or low gears, as well as on the teeth of the couplings and on the splines of the front axle drive shaft - Clean off nicks and burrs, replace damaged parts parts
Difficult gear shifting or differential locking:
- Jamming of couplings on the splines of the hub, differential housing, front axle drive shafts - Clean burrs, nicks or scuffs, replace damaged parts
- Nicks on the teeth of the small ring gear of the high or low gears, as well as on the teeth of the couplings and on the splines of the front axle drive shaft - Clean nicks and burrs, replace damaged parts
- Bent fork or rod - Straighten deformed parts
- Jamming of the drive lever on the axles - Remove the lever, clean the axles and bushings. Replace damaged parts. Lubricate the parts with lithol
- Contamination or corrosion in the control drive joints - Clean the parts, replace the damaged ones
Spontaneous disengagement of gears or differential lock:
- Worn teeth of gears and clutches - Replace the worn parts
- Reduced elasticity of the locking springs or wear of the locking parts - Replace the springs or worn parts
- Incomplete gear engagement and lack of differential lock due to deformation of drive parts or due to nicks on gears, clutches and splines - Straighten or replace deformed parts, clean nicks and burrs, replace damaged parts
Oil leak:
- Damaged sealing gaskets - Replace gaskets
- Loose nuts and studs securing covers to crankcase - Tighten nuts and studs
- Worn or damaged shaft seals - Replace seals
- Worn transfer case drive rod sealing rings - Replace sealing rings
- Presence of cavities, porosity and damaged surfaces of body parts - Replace body parts