Gear selection mechanism VAZ 2110 faults

Almost every driver has gone through the domestic auto industry, and everyone knows firsthand about its problems. Many can be easily treated at minimal cost. This post will not open America to anyone, but I will still write briefly how you can do all this yourself.

On the 10th family, gear shifting is generally convenient, but the moves are a bit too big. Like a typical pelvic driver, I installed a short-stroke and a Kalino card www.drive2.ru/l/2206012/, and there were problems with engaging the reverse gear. It's all about the white plastic under the gearshift knob cover, which is the guide and limiter for 1.2 and 3.x. I cut it, everything seems to be working, but somehow it’s all wrong... During the next gearbox overhaul, I installed a screw lock with a preload of 4.5 kg, a pair of 4.1 from 2108 and replaced the gear selection mechanism from 2108. After that, I removed the white plastic as unnecessary and put washers under the lever ball so that it does not move down. Everyone knows the differences between switching on s.h. on 2110 and 2108. Shifts have become clear, adjusting the rocker has become much easier))) More precisely, now you don’t need to adjust it at all, you just select a convenient position for the gearshift lever and tighten it. After 50t.km. again I had to disassemble the gearbox in order to increase the preload in the helical differential from the already 3kg to 7kg. The assembly took a little longer and this turned out to be to my advantage. In a friend’s garage I saw live an amplified sample of a clubturbo, the only amplification in it was a jumper plate in the form of a horseshoe between the “mustache”. Well, I studied it))) and went to the garage to repeat what I saw. I examined my sample, which had worked 50 thousand km, and noticed that the whiskers had indeed spread apart from each other. I pressed them back in a vice and began to model the horseshoe-amplifier, first from cardboard. Then I made it from 5mm hot-rolled sheet metal. I decided that I could make it more powerful, and taking into account the errors, I made its final version. You need to cook it carefully, preferably with a semi-automatic machine, so as not to shit too much, otherwise it will be very difficult to get to the excess scale! During assembly, I also replaced the switching rod with a 2108 one. Many friends advised me when installing a sample from 2108. I also installed a rubber boot from the Priora, since the one from 2110 was constantly torn after installing the Kalino cardan. Another issue I noticed was that the inner two roller bearings rotate directly on the secondary shaft. There was only one way out, grab it by welding...

After assembly, the activation became clearer, the longitudinal strokes remained the same, but everything was still about 2 times less than that of a standard rocker, but the transverse ones decreased, the horseshoe is in action! Still, such a small piece of hardware, but it does its job)))

Intervention in the VAZ-2110 gearbox is required in cases where extraneous noise and shifting problems are observed. To perform repairs, you will need new items, consumables, appropriate tools, a vehicle operating manual and the recommendations given in this article.

How does the VAZ 2110 gearbox work?

Before repairs, it is advisable to understand the operating principles of the gearbox installed on the VAZ 2110 model. The operating principle of the gear unit is as follows:

The device contains a primary shaft consisting of a gear block. They are in constant mesh with the gears designed to move the car (drive gears);
A drive gear is installed on the second shaft, on which the synchronizers are located. The bearing and oil sump are also installed here;
by means of a flange, the driven gear of the main gear is connected to the two-satellite differential;
elements of the device also include rods, ball joints, levers and switching mechanisms;
so that the speed does not “take off”, the unit is equipped with a jet thrust, the ends of which are fixed to the power unit and support.

Repair kit for VAZ 2110 gearbox 4th gear (up to 10.2000) Buy at a price of 1429 rub.

Dear customers, in order to avoid errors when sending a set of 4th gear gears for a VAZ 2110 gearbox, please indicate your car model, year of manufacture, and month in the “Comment” line.

Any car of the VAZ family has a gear shift mechanism, which consists of a gear shift lever, a ball joint, a rod, a gear selection rod and a gearbox.

The gearbox is designed to change the torque developed by the engine in order to obtain different traction forces on the drive wheels when starting the car, accelerating, moving and overcoming road obstacles; changes in vehicle speed and direction; the possibility of driving the car at low speeds, which cannot be provided by the engine, and disconnecting the engine from the transmission for a long time when parked or when the car is moving by inertia (coasting).

The main difference between the VAZ 2110 gearbox repair kit and the VAZ 21083 repair kit:

— absence of an oil hole on the inner surface of the VAZ 2110 gear rings.

The repair kit 2110 -1701146 RK includes:

4th gear gear of the secondary shaft 2110 – 1701146 – 1 pc.;

3-4 gear synchronizer clutch assembly 2110 - 1701116 -00 - 1 pc.;

Synchronizer blocking ring 2108 – 1701164-00 – 1 pc.;

The VAZ 2110 gearbox is a two-shaft, five-speed gearbox, which is combined with a differential and a main gear, and is activated by a lever located in the car's interior.

1 – nut; 2 – ball bearing; 3 – thrust washer; 4 – bearing sleeve; 5 – needle bearing; 6 – 4th gear gear; 7 – bearing spacer ring; 8 – synchronizer blocking ring; 9 – sliding clutch for synchronizer of 3rd and 4th gears; 10 – sliding coupling hub; 11 – third gear gear; 12 – retaining ring; 13 – thrust half-rings of the secondary shaft; 14 – 2nd gear gear; 15 – sliding clutch for synchronizer of 1st and 2nd gears with reverse gear; 16 – retaining ring of the synchronizer hub; 17 – hub of the sliding clutch for the synchronizer of 1st and 2nd gears; 18 – synchronizer spring; 19 – cracker; 20 – retainer; 21 – 1st gear gear; 22 – roller bearing; 23 – thrust washer; 24 – bearing sleeve; 25 – fifth gear gear; 26 – sliding clutch hub; 27 – sliding clutch of the 5th gear synchronizer; 28 – thrust plate.

The VAZ 21083 gearbox housing is made of aluminum alloy and consists of 3 parts: gearbox housing, clutch housing and rear gearbox housing cover. A gasoline-oil-resistant gasket sealant is applied between the parts. The crankcase socket is equipped with a special magnet on which metal wear residues are collected.

The input shaft is a block with drive gears that are constantly engaged with the driven gears of the forward gears. The hollow output shaft is equipped with a removable final drive gear. This shaft contains the driven gears of the forward gears 1st, 2nd, 3rd, 4th, 5th and their corresponding synchronizers - for 1st and 2nd, for 3rd and 4th and – for the 5th.

The shafts are equipped with front roller bearings (18, 12) and rear ball bearings (3, 37). The radial distance in ball bearings should not exceed 0.04 mm, in roller bearings - 0.07 mm.

The gear shift mechanism is used to change gears in the box and is controlled by the driver using a lever from inside the car. To prevent spontaneous gear disengagement, a reaction rod is introduced into the gearbox control drive, one end of which is connected to the power unit, and a ball joint clip is attached to the other end.

The oil level in the VAZ 2110 gearbox (gearbox) should always be “at level”. After all, even a slight drop can ruin fifth gear. A gearbox is not an engine; the oil in it does not “burn” and disappears only due to leaky seals.

The VAZ 2110 gearbox is filled with TM-5-9p oil from the factory, which is designed for a mileage of 70-80 thousand kilometers.

Transmission repair is necessary for the following symptoms: noise when shifting gears, difficult shifting on and off, spontaneous shifting of gears, transmission oil leakage.

In some cases, you can get by just adding oil. If the signs of malfunction have not disappeared, it is necessary to proceed to repairing the gearbox. The first option is to contact a service station. Repairing a VAZ 2110 gearbox is quite possible in your garage.

Other articles of the product and its analogues in catalogues: 2110 -1701146 RK, 2110 -1701146-00, 21080170114600.

VAZ 2108, VAZ 2109-099.

Any breakdown is not the end of the world, but a completely solvable problem!

How to independently replace the fourth gear repair kit on a car of the VAZ 2108-21099 family.

With the AvtoAzbuka online store, repair costs will be minimal.

Just COMPARE and BE SURE.

Don’t forget to share the information you find with your friends and acquaintances, as they may also need it - just click one of the social networking buttons located above

Adjusting the gearbox, video instructions

If it is necessary to replace gears, bearings or other parts, the box must be dismantled. Usually in such cases, the VAZ 2110 gearbox is overhauled and elements that have failed are replaced. But removing the box is not always necessary.

It is known that the 10 has problems with gear shifting. In fact, the speed is knocked out.

To eliminate the problem, the unit is equipped with a special mechanism that allows you to adjust the drive.

The operation is performed in the following cases:

the gearbox was dismantled due to repairs, for example, replacing the input shaft bearings;
speed knocks out while driving;
Gears don't engage or disengage easily.

If such situations arise, then adjustments cannot be avoided.

Of course, performing this procedure is much simpler than dismantling work. The work is performed in the following sequence:

At the bottom of the vehicle there is a nut in a bolt. This fastener holds the transmission linkage in place. The fastening element does not need to be removed: just unscrew the nut a little;
to move the grooves of the rod and the slot of the fastening clamp apart, just use a flat screwdriver;
the rod must be set to the neutral position. Then you need to remove the cover from the gearbox handle;
then the lever is set in accordance with the template;
at the next stage it is necessary to adjust the backlash of the rear vector rod;
adjusting axial play;
At the final stage, the fastening must be installed in place and tightened.

Repair kit for VAZ 2110 gearbox, 3rd gear, new model (after 10.2000)

Dear customers, in order to avoid errors when sending a set of 3rd gear gears for a new VAZ 2110 gearbox, please indicate your car model, year of manufacture, and month in the “Comment” line.

Any car of the VAZ family has a gear shift mechanism, which consists of a gear shift lever, a ball joint, a rod, a gear selection rod and a gearbox.

The kit includes 2110-1701131-10 RK:

3rd gear gear 2110-1701131-10;

3rd gear clutch with synchronizer hub assembly 2110-1701116;

Synchronizer blocking ring 2110-1701164.

The gearbox on the VAZ 2110 is a two-shaft, five-speed gearbox, which is combined with a differential and a main gear, and is activated by a lever located in the car's interior.

1 – rear cover of the gearbox housing, 2 – fifth gear drive gear, 3 – input shaft ball bearing, 4 – fourth gear drive gear of the input shaft, 5 – input shaft, 6 – third gear drive gear of the input shaft, 7 – gearbox housing , 8 – drive gear of the second gear of the input shaft, 9 – reverse gear, 10 – intermediate reverse gear, 11 – drive gear of the first gear of the input shaft, 12 – roller bearing of the input shaft, 13 – input shaft oil seal, 14 – breather, 15 – clutch release bearing, 16 – clutch release bearing clutch guide sleeve, 17 – main gear drive gear, 18 – secondary shaft roller bearing, 19 – oil sump, 20 – satellite axis, 21 – speedometer drive drive gear, 22 – axle shaft gear, 23 – differential box, 24 – satellite, 25 – clutch housing, 26 – oil drain plug, 27 – main drive driven gear, 28 – adjusting ring, 29 – differential tapered roller bearing, 30 – axle shaft seal, 31 – first gear driven gear secondary shaft, 32 – synchronizer of the first and second gears, 33 – driven gear of the second gear of the secondary shaft, 34 – driven gear of the third gear of the secondary shaft, 35 – synchronizer of the third and fourth gears, 36 – driven gear of the fourth gear of the secondary shaft, 37 – secondary ball bearing shaft, 38 – driven gear of the fifth gear of the secondary shaft, 39 – fifth gear synchronizer, 40 – secondary shaft.

The gearbox housing on the VAZ 2110 is made of aluminum alloy and consists of 3 parts: gearbox housing (7), clutch housing (25) and rear gearbox housing cover (1). A gasoline-oil-resistant gasket sealant is applied between the parts. The crankcase socket is equipped with a special magnet on which metal wear residues are collected.

The input shaft (5) is a block with drive gears that are constantly engaged with the driven gears of the forward gears. The hollow output shaft (40) is equipped with a removable final drive gear (17). On this shaft there are driven forward gears 31 - 1st, 33 - 2nd, 34 - 3rd, 36 - 4th, 38 - 5th and their corresponding synchronizers 32 - for 1st and 2nd -th, 35 – for the 3rd and 4th and 39 – for the 5th.

The shafts are equipped with front roller bearings (18, 12) and rear ball bearings (3, 37). The radial distance in ball bearings should not exceed 0.04 mm, in roller bearings - 0.07 mm.

The VAZ 2110 gearbox is filled with TM-5-9p oil from the factory, which is designed for a mileage of 70-80 thousand kilometers.

Transmission repair is necessary for the following symptoms: noise when shifting gears, difficult shifting on and off, spontaneous shifting of gears, transmission oil leakage.

Other articles of the product and its analogues in the catalogues: 2110-1701131-10РК, 2110-1701131-10, 21100170113110.

VAZ 2110-2111, VAZ 2112, VAZ 2113-2115.

Any breakdown is not the end of the world, but a completely solvable problem!

How to independently replace the third gear repair kit on a VAZ 2110 family car.

With the AvtoAzbuka online store, repair costs will be minimal.

Just COMPARE and BE SURE.

Don't forget to share the information you find with your friends and acquaintances, because they may also need it - just click one of the social networking buttons located above.

Transmission repair

Adjustment does not always achieve the desired effect. Therefore, the motorist will need to carry out repair work. Practice shows that most often the gears that are responsible for the first and second speeds are knocked out. When disassembling, the car owner needs to make sure that all fasteners are in good condition. We are talking about 3 springs. 1 design serves the first and second speeds, 2 - the third and fourth, and 3 - the fifth. The first clamp has the maximum length.

Before repairing a VAZ 2110 gearbox with your own hands, it is recommended that you carefully study the video material, as well as read the operating manual.

Backstage replacement and repair

Taking into account the fact that during the operation of a car, the rocker on a VAZ or on any other car experiences constant loads, the mechanism wears out, and the adjustments get lost. For this reason, it is important to understand what in a particular case would be the optimal solution: repair, adjustment or replacement of the link with a standard new one or a short-stroke one.

In any case, it is necessary to first disassemble the mechanism. To do this you will need:

remove the cover on the gearshift knob;
drive the car onto a pit or overpass/lift;
remove the tunnel where the gearshift knob is installed by unscrewing the bolts;
dismantle the rocker itself (on a VAZ 2110 it is secured with six bolts).

During the disassembly process, you need to carefully check the condition of each individual part, you should also bend the boot, check the condition of the support, oil seal, cardan, etc.

If, for example, the oil seal has failed, then it is enough to have a repair kit where such an oil seal is included. This kit will also come in handy if more complex repairs to the backstage are required.

If the bushing is deformed, it must be replaced. In the event that the cardan is loose, as well as in a situation where the hole in the lever axis is worn out, a complete replacement of the link will be required, that is, a repair kit will not be able to solve the problem.

We also note that a common problem that drivers note during operation is the rattling of the rocker. Typically, in this case, if there are no other complaints, the drawstring cushion is often the culprit.

At the same time, replacing the rocker cushion is not a complicated procedure, but the result is often positive and significantly increases the comfort when operating the vehicle.

Another important procedure in the process of servicing the rocker is replacing the rocker rod oil seal. It is important to understand that the serviceability of not only the operation of the backstage, but also the gearbox directly depends on its condition.

If drops of transmission oil are visible under the car, this often indicates that the seal is leaking. As a rule, problems with the VAZ 2110 rocker seal appear in the form of a crunching noise when switching.

We also recommend reading the article on how to remove the gear shift lever. From this article you will learn about the features, subtleties and nuances that need to be taken into account when removing the gearshift lever.

As for replacing the oil seal, the car needs to be driven into a pit or raised on a lift. Next, you should inspect the rubber boot. If it is not sealed or is torn, traces of oil will be visible.

Then you should bend the boot, disconnect the cardan and thus gain access to the cuff. Now the cardan is removed from the lever, after which it is disconnected from the rocker. After removal, you can get to the oil seal and then use an awl or hook to remove the gearbox cuff.

Next, you should press in a new oil seal (in home-made conditions, installation is carried out using a stopper from a plastic bottle). If the oil seal is installed successfully, you can proceed to reassembling the entire mechanism, not forgetting to put the boot in place.

In fact, such repairs allow you to avoid oil leaks in the gearbox and improve the operation of the gear shift mechanism. Finally, we note that it is also important to carry out adjustments and settings after repairs.

The fact is that even a serviceable, but incorrectly configured rocker will not work properly. By the way, on a VAZ 2110 it’s difficult to set up the rocker yourself. To make the process easier, it is better to immediately invite an assistant.

Difficulty engaging second gear, video

The owner of the ten may encounter the same problems as when turning on the first speed. In any case, malfunctions are due to the following reasons:

abrasion of gear teeth. At the first stages, the speed turns on poorly, but over time it will start to crash. Therefore, surgical intervention is required;
there is insufficient adhesion of the gear to the gear shift clutch;
the speed is switched off when hitting uneven road surfaces. In this case, the problem is the clutch.

Sometimes, to eliminate the knockout of the second gear, it is enough to replace the clamp. If replacement does not achieve the desired result, then a major overhaul is required.

Adjustment in this case will not solve the problem. Carrying out repair work yourself is quite difficult. Unlike adjusting and replacing oil seals, major repairs require professional skills.

Nuances, video

It should be noted that the gearbox is a fairly stable component of the vehicle. Compared to other units, breakdowns occur much less frequently here. At the same time, you need to remember that for the normal functioning of the box, you should change the oil in a timely manner, and use products from trusted brands. In terms of their performance, the gearboxes are almost identical. If we are talking about front-wheel drive cars, which include the VAZ-2110, then you can use oil poured into the power unit. If we are talking about rear-wheel drive VAZs, then special oil is provided for them. Sometimes car owners notice an oil leak. This is caused by weak fastening of the box and crankcase. The problem is solved with the help of seals, as well as careful tightening of the bolts.

If problems arise with the box, first of all it is necessary to adjust the drive and replace parts that have failed as a result of physical wear.

If the car owner has the skills and experience, then repairing the gearbox of a VAZ-2110 car can be done with his own hands. In other cases, it is better to visit a trusted auto repair shop and eliminate the deficiencies after professional diagnostics.

Where can I buy

You can buy a new replacement part at special retail outlets or HERE.

The cost of the checkpoint varies, starting from 50,000 tenge

Help

If you haven’t coped with this task yourself or simply don’t want to bother with the work, you should contact a service station, which you can choose HERE.

The VAZ 2110 has been produced for several years now, because all the “sores” of these cars have long been known, both to ordinary owners of “ten” cars and to VAZ itself. The latter seems to be trying to gradually solve these problems, but very gradually. But that's a completely different story, as they say.

Common gearbox problems

Owners of the VAZ 2110 car note several characteristic faults in gearboxes for this model. Some people do not engage reverse gear, others complain about overshoot, and so on.

Let's look at the most popular problems that the domestic "ten" box can boast of.

First speed problem. It may fly out or be difficult to turn on in the car. There are several reasons:

The synchronizer has failed;
The latch spring has a defect, it has burst;
The lever has become loose, causing the gears to switch spontaneously;
The rod is out of order or the fork is faulty; they must be replaced.

Second gear problem. It often gets knocked out, or it’s difficult to switch to it. There may also be several reasons for such a malfunction:
The gear teeth do not cling well to the gear shift clutch;
The tips of the teeth are worn out and worn out, making it difficult to switch on the speed. Over time it will begin to fly out. Therefore, repairs are required;
If the gear is knocked out when hitting a bump, then there is nothing good about it - the problem lies in a failing clutch.

Having experience, relevant knowledge and skills makes it possible to deal with checkpoint problems with your own hands. If all this is missing, we strongly recommend that you contact a trusted service center, where they will carry out diagnostics, determine the true causes of the problem and return your gearbox to its previous condition. Yes, it will cost some money, but you can’t do without it. Nothing is eternal. Moreover, the “tens” gearbox.

Lost reverse gear on VAZ 2110

Often this mechanism is broken and the rear one turns on instead of the first one. It turned out that way for me too.

On VAZ 2110 , 2111, 2112 cars, reverse gear is engaged by pressing the lever down-left-forward. If the mechanism is broken, then both gears shift to the left and forward. And next to each other. Rear - to the left all the way. The first one is a little short. Without skill, it is easier to hit the back one than the first one. Apparently people after nine try to turn it on in the same way: to the left all the way and push it further forward. As a result, either the lining breaks (the new one is shown in the photo):

Or plastic on the axle (pictured is mine, worn out and broken):

You can change the axle directly from the car interior. The overlay too, I think. In order to get to the mechanism you need to remove the leatherette cover.

It is held on a frame. Frame with snaps. Latches in the middle. It is enough to pick up two and pull out the frame.

READ Replacing the overrunning clutch of the Passat b5 generator

Lift it up and we will see the cover and the axle with a plastic tip (I don’t know how to do it correctly).

When you press the lever down and to the left, the tip fits into the groove, which allows you to deflect the lever more to the left and get into reverse gear. If you didn’t press the lever, but simply moved it to the left, then it rests on the pad and doesn’t go further to the left—we end up in the first one.

In order to replace the axle, you need to remove the screw and nut:

The M8 nut can be unscrewed with a 13mm wrench. But the screw could not be unscrewed right away. First I tried it with a cardan at 90 degrees. Then I unscrewed one self-tapping screw to widen the gap in the plastic:

And he stuck a thin slotted screwdriver in there, while tilting the lever to the right:

Next, remove the axle and insert a new one. And everything is in reverse order. Everything is done in 20 minutes. I spent more time running around for screwdrivers.

Spare parts:1. Repair kit for gearbox shifter for cars of the LADA 110 family - cost 154 rubles.

The car's transmission allows you to change the torque from the internal combustion engine before transmitting it to the drive wheels. This makes it possible to change the speed of the vehicle, maintain engine operation in the optimal speed range, etc.

Also, thanks to the gearbox, you can change the direction of movement, that is, the vehicle gets the opportunity to move not only forward, but also backward. At the same time, on cars for forward movement, step boxes have several gears, while there is only one reverse speed.

It should be noted that quite often drivers encounter a malfunction when reverse gear , and on different types of gearboxes (manual transmission, automatic transmission, manual transmission, etc.). Next, we will look at the main reasons why reverse gear does not engage in manual transmissions, as well as in automatic transmissions.

Repairing a gearbox by hand, how to bring spare parts into the desired form

If it is necessary to replace the rod hinge, remove the protective cover on it, and then unscrew the bolt securing the hinge. For strength, a special glue TB-1324 was applied to the bolt. Therefore, before assembly, it is necessary to clean the bolt and apply this glue to the surface.
Check the magnet, if it is intact, just clean it of dirt. If small cracks are found or if it does not magnetize well, it should be replaced.
Clean the surfaces of the gearbox housings, clutches and rear cover from sealant.
Using transmission oil, lubricate all rotating elements.

We disassemble the VAZ 2110 gearbox housing

The entire preliminary disassembly process most likely took you no more than 10-20 minutes of time. Having spent just a little effort, we will continue repairing the gearbox for the VAZ 2110, for which we will disassemble the crankcase and the operating mechanism:

1. Unscrew the three M13 spring plugs securing the gear rods. Along with the springs, the end balls will also fall out of the holes, so you should be careful not to lose them. We do the same with the retainer plug for reverse gear, remove the ball using a magnetic screwdriver;
2. The VAZ gearbox housing is attached to the clutch housing with a large number of M13 bolts and one nut. Unscrew them all one by one. To break the tight engagement of the mating planes of the crankcases, “undermine” them with a screwdriver in a special groove;
3. Unscrew the first and second gear fork from the rod, held by an M10 bolt. Having slightly raised the fork with the rod, remove them;
4. Do the same for third and fourth gear. To remove the rod, disengage it from the gear shift mechanism. In the same way, remove the rod for fifth gear from engagement;
5. Remove the axis of the reverse intermediate gear and the gear itself;
6. Now you can sequentially remove from the seats: simultaneously both shafts with a set of gears and the differential; the gear mechanism is also easily removed from the crankcase housing, held by three bolts;
7. Release the gearbox rod by unscrewing the M10 bolt of the drive lever.

Repairing the box

In the event that this kind of adjustment work did not bring much results, you will have to remove and disassemble the gearbox of your VAZ 2110

The main attention should be paid to the gears, as they are most often knocked out. This is especially true for first and second speeds.

It will also be important to check the latch. There are three latches in total in the gearbox.

The very first of them is very long and is responsible for 1st and 2nd gears. Next comes the clamp for third and fourth gears, and the shortest of the clamps is intended for 5th gear

There are three latches in total in the gearbox. The very first of them is very long and is responsible for 1st and 2nd gears. Next comes the clamp for third and fourth gears, and the shortest of the clamps is intended for 5th gear.

complete gearbox assembly

Often, VAZ 2110 owners voice a problem regarding the switching or departure of first gear. Most likely, the reasons lie in the following:

synchronizer problems;
damage to the retainer spring when the lever dangles and the gears are switched on randomly;
damaged rod and fork.

A common problem is when the second gear is reluctantly engaged, or it is simply knocked out. The most likely causes of the problem:

poor engagement of the gear and clutch that engages the gears;
wear of gear teeth and coupling;
problems with the clutch.