DIY gearbox repair on a VAZ 2109: detailed structure and how to disassemble it

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VAZ 2109 and 21099 cars are equipped with four- and five-speed manual transmissions. All gears, except reverse, are equipped with synchronizers. The box is also combined with the differentials.

Useful tips

It is extremely important to monitor the serviceability of the gearbox, and if signs of breakdown are detected, fix them immediately. Do it yourself or with the help of a car service - this is your personal decision.

When operating a car in city conditions, you have to change gears more often. Therefore, it is recommended to use motor oil here. This ensures that the synchronizers remain effective longer. Transmission oil is better suited for highways, increasing the life of bearings and gears, although the synchronizer lasts less.

Internal structure of the box

Tuning the gear knob

Breathing a new spirit into the design of the gear knob is very simple. Today in stores you can see a huge assortment of the most sophisticated accessories in design. But it’s quite reasonable to create something yourself, for example, illumination of the VAZ-2109 gearbox handle. To do this, you should invest in a new pen, the model of which is suitable for these purposes.

When choosing a handle, pay attention to the presence of grooves and holes for wires. Usually the part of the handle on which the gears are marked is not visible because the numbers are chrome-plated. But this shortcoming can be completely corrected.

You can purchase ferric chloride at any chemical store.

Pour the ferric chloride solution into a glass container and place the lid in it. After 10 minutes, remove and rub with a brush. Repeat the operation until all the chrome coating has disappeared. To speed up the reaction, you can add a little hot water to the solution. Next, install the light bulb and wires into the handle body. And now, the new unusual gear knob is ready.

Device

To understand the essence of repairing, disassembling and assembling a gearbox, first of all you need to get acquainted with its structure. In the case of the VAZ 2109, the box structure is as follows:

On the input shaft there is a block of drive gears that are in constant mesh with the driven gears of the gears when moving forward;
The second shaft has driven gears with needle bearings. There is also a pair of synchronizers located there;
The secondary shaft is created together with the drive gear of the main transmission;
The driven gear of the main gear is attached to the flange of the two-pinion differential box;
Differential bearings are always mounted with interference, which is adjusted by selecting rings of different thicknesses.

Checkpoint diagram

Operating principle of the gearbox synchronizer

Anyone who has ever driven a car knows the purpose of a gearbox. However, both its structure and operating principle often remain a mystery to many. In general, this may be correct, in any case, this approach has a right to exist, however, without studying the box in detail, it is worth touching on such an element as the synchronizer.

Why are gearbox synchronizers needed?
Transmission synchronizer operation
Gearbox synchronizer, care, operation

Malfunctions and their elimination

Gearbox repair largely depends on the nature and type of fault. There are several options for the breakdown of this unit, in each of which appropriate actions should be taken to eliminate them.

Malfunction	Possible reasons	What do we have to do
There is noise in the gearbox	The teeth on the gears are worn out; Bearings are worn out; The oil level in the gearbox has decreased	Add oil; Replace worn bearings; Replace seals if necessary
Gears are difficult to shift	The clutch is not fully depressed; The rod that controls the gear shift mechanism has become deformed; The integrity of the jet thrust has been compromised; The joint or rod that selects the gear is loose; The speed change drive is incorrectly adjusted; The plastic components of the gear shift drive are broken	Try straightening the rods. If this is not possible, replace them; Tighten the mounting screws more tightly; Adjust the gear shift drive; Replace damaged components
Spontaneous gear disengagement occurs	The ends of the synchronizer teeth on the gear and clutch are damaged or worn; Cracks appeared, the rubber on the rear supports delaminated; The gear shift drive was adjusted incorrectly; The traction guard was not tightened correctly, which is why the gear is not engaged completely	Replace worn, deformed elements; Correct the position of the rod casing; Adjust the drive
Gears are switched on with noise and crackling	The clutch does not disengage completely; The locking ring of the gear synchronizer, which is engaged, is worn out	Replace the locking ring
There is an oil leak from the gearbox	Wear of the input shaft oil seal; Wear of the rod speed selection; Breakage of the speedometer drive shaft seal; The cover on the gearbox or crankcase is loose; The sealant under the gearbox cover is damaged; The drain hole closure is loose	Replace gaskets, use new sealant and gaskets; Tighten all existing fasteners; Check the condition of the drain plug

In most cases, problems with the gearbox are eliminated by dismantling and disassembling it. Do not take on this type of work without the proper skills and experience.

Disadvantages, breakdowns and problems of the Lada Samara box

The reliability of the manual transmission is weak, the transmission is famous for unclear shifts and howling

Gears switch off spontaneously due to wear of the locks on the couplings and gears

The box hums most often due to a lack of lubrication or when the bearings are damaged.

A strong crunch when switching hints at a quick replacement of synchronizers

The weak point of the gearbox is the rocker; it often requires repair or replacement

Another common problem is oil leaks from different seals.

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Dismantling

To dismantle the box, we recommend that you rely on the instructions, strictly follow the sequence and reinforce your skills with visual videos.

Disconnect the negative terminal from the battery and drain the oil from the gearbox system.
Unscrew the bolts that hold the crankcase guard in place and remove it.
Disconnect the ground (wire) from the clutch housing.
At the end of the clutch cable, loosen the tension on the nuts slightly.
Remove the cable end from the clutch lever.
Disconnect the block from the traction relay.
Disconnect the wire going to the starter traction relay.
Dismantle the starter itself directly.
Disconnect the drive rod from the joint tip. We are talking about traction, which switches gears.
Disconnect the cable from the car's speedometer drive.
Unscrew the tie rod ball joint.
Remove and press the steering rod hinge pin out of the strut swing arm.
The shank of the inner CV joint of the front wheel drive should be pressed out and moved to the side.
Disconnect the second CV joint.
Remove the clutch housing shield.
Release the gearbox from the fasteners holding it to the engine.
Remove the box.

Carefully remove the gearbox

Be sure to move it horizontally away from the motor before directly removing the box. Then disengage the input shaft. Be careful not to damage the clutch spring petals.

Removing the VAZ 2109 gearbox

First of all, you need to remove the mudguard and engine crankcase protection (if installed).

drain the oil from the box, remove the drive nuts and wheels. If removal takes place in a pit, it is necessary to jack up and hang the front part of the car on trestles or other reliable stands. Be sure to disconnect the battery terminals. The next order is:

– remove the clutch cable

Disassembly

Having removed the gearbox, you can proceed directly to the main thing - disassembly. This will allow you to change damaged elements as you work, identify existing faults and solve problems on your own.

Clean and thoroughly wash all external surfaces of the gearbox.
Place the box in a vertical position and remove the back cover.
Remove the clutch cable bracket, then use a rubber hammer to knock the rear cover off the gearbox.
Remove the old gasket. She will be replaced.
Engage any of the two gears - 3 or 4.
Unscrew the bolt that holds 5th gear, then turn it on.
Simultaneously turning on the indicated speeds will allow you to fix the shaft and prevent it from turning.
Unscrew the nut on the secondary shaft, and then on the primary one.
Remove the 5th speed synchronizer along with the fork.
Remove the fork from the coupling. Remove the synchronizer as carefully as possible. If you allow the clutch to move away from the hub, the spring-loaded balls that secure the synchronizer will simply fall apart.
Remove the 5th speed synchronizer locking ring.
Remove the 5th speed driven gear from the output shaft.
Remove the thrust ring located on the needle bearing.
Remove the needle bearing itself from the 5th speed gear.
Remove the drive gear from the drive shaft and remove the bearing plate.
Now the needle bearing bushings should be removed from the secondary shaft, and the thrust washer should also be removed.

Jewelry work

Take out the ring that secures the input shaft bearing, and then a similar ring for the secondary shaft.
Unscrew the locking plug and remove the ball and locking spring. Next you can get a couple more clamps.
Remove the rear engine mount.
Unscrew the reverse gear lock plug, tilt the box and thus remove the lock ball and spring.
Remove the clutch housing and gearbox housing mounting bolts.
Acting as carefully as possible, separate the two units. To do this, there are grooves in the crankcases into which the ends of a screwdriver are inserted. By shaking, you can disconnect the elements without any problems.
Remove the gearbox housing.
Unscrew the bolt securing the 1st and 2nd speed shift fork.
Remove the fork and stem.
Unscrew the bolt securing the 3rd and 4th speed forks.
Separate the rod head from engagement with the lever, remove it along with the fork from your gearbox.

When disassembling the box into parts, be sure to pay attention to the condition of the elements. If you detect faults in time and replace gearbox components, you can get by with inexpensive but very effective DIY repairs.

Disassembled gearbox

What to pay attention to

So, following the instructions, we disassemble the gearbox of your VAZ 2109. Along the way, pay attention to the following points:

Bearings. When they wear out, a noise from the box occurs. Plus, worn bearings negatively affect the condition of other gearbox elements;
Synchronizers and sealing washers. If their condition leaves much to be desired, then the gears shifted poorly precisely because of them. Replace them;
Clutch system, cotters, coupling hub clamps. All this must be replaced separately if there are signs of wear or defects;
Blocking rings, synchronizers. If there are chips or nicks, don’t even think about alternative solutions, replace them immediately;
Bearing tracks. Over time they wear out. If signs of wear are found, perform a complete replacement. In this state, they were only a short time away from breaking;
Gap between gears and locking rings. Normally it is no less than 0.6 mm. In case of deviations, there is only one solution - replacing the rings;
Retaining rings. If elasticity is lost, these elements must be changed, since they will no longer be able to perform their functions.

When assembling the gearbox, do not forget to lubricate the new gaskets with a layer of lithol. And when pressing the oil seals, do it with the working edge inward. The metal clip should be located on the outside.

During the process of reassembling the gearbox, all rubbing components should be treated with oil, and do not forget about the sealant for connecting the clutch housings and gearbox. Doing everything yourself is quite possible.

Gearbox configurations

Below are the most successful gearbox configurations depending on the engine. For a more detailed selection, you can use a calculator on the Internet.

The most suitable gearbox configuration for a civilian naturally aspirated engine: 18 row gearbox + main pair 3.9.
The most suitable gearbox for a sports naturally aspirated engine: 7th row gearbox + main pair 4.3.
The most suitable gearbox configuration for a turbo civilian engine: row 104 + main pair 3.5.

The differential is two-satellite, the tension is adjusted by different thicknesses of the adjusting ring.

Sports cars often use a differential lock.

A differential lock is a mechanism that locks the differential so that both wheels rotate evenly. Initially, locking was used on SUVs to ensure that the front and rear axles rotated evenly.

In our case, screw locks are especially popular, because they are easily installed in the gearbox, increase cross-country ability on wet roads, and provide an advantage during acceleration due to uniform constant rotation of the wheels.