Single axle tractor engages gear but does not go

If the rear gear of the automatic transmission doesn’t work

First, it is missing. is an indicator of a serious malfunction. Secondly, this failure usually leads to further hassle and waste of money. And, thirdly, with a missing gear, after all, there is no way to continue further adequate driving. You may drive further without it, but if you get to a parking lot, for example, the driver risks “getting stuck”. As a rule it is impossible to park without a reverse gear in crowded cities. Leaving the machine in the middle of the road or to be eaten by a tow truck is also not an option.

single, axle, tractor, engages, gear, does

Setting the plough on “Neva MB-2” power tiller

The plow is attached to the frame with an adapter or hitch. The tines are lifted to the ploughing depth with no tilting. The vertical strut is exposed. It maintains verticality when the field-board is touching the ground for a subsequent 30 mm heel lift.

Setting the angle of repose: a shoe is put under the left turnbuckle and the plough leg is set in a vertical position. Tighten the connections, finished. The handle bars are set at waist level. reducing the strain on your arms and shoulders.

Clutch device on MB 90 m power tiller. Kadwi power tiller operating instructions

Hello. single axle tractor Kadvi on the fourth gear is, how should I say it. “slippage”, he drives, pulls, and then as if the gear leaves the clutch and with a bang back into the clutch, tell me this is a problem with the clutch or with the gearbox? This only happens in fourth gear, sometimes just crunching gear is engaged, the clutch is released, single axle tractor does not go, in the box is something crunchy.

In your case the problem is with the gearbox. The problem can be solved, but unfortunately diagnosis is not possible without disassembling the unit. Below you can find instructions for repairing the tractor with a similar problem, but if you’re not sure you can cope with the repair yourself, I recommend that you apply to the workshop “single axis tractor-master”: For repairs, service and spare parts (including by mail) for power tillers, mini tractors and other garden equipment, please contact the workshop at: 223021 Minsk district, Alg. Ozertso str. Zelenaya 18, tel. 8 029 6741674, 8 017 5123712.

The gearbox in the motor block Kadvi MB 90 is considered a reliable and resourceful unit. Unfortunately with the lapse of time problems with the gearbox, like yours, are inevitable.

The gearbox remote is very nicely done, just like in Ferrari or Lamborghini. The shifting lever moves in an H-shaped pattern, it is easy to engage and well fixed gears. In principle, the single-axle tractor is not bad, in time you can install a less capricious engine more powerful. Unfortunately, it is difficult to find parts for the Kadvi, this is the main disadvantage of this machine.

Let’s start with the repair. No movement in third gear, crunch in gearbox.

First of all, we drain the oil from the gearbox, the cap has a screwdriver slot, without a special tool it is difficult to unscrew.

One of the shafts in the gearbox is fixed inside under the clutch, so we remove the engine, for this disconnect the throttle and clutch cables, ignition wire.

We remove the control panel (steering wheel, steering boom).

Next step, remove the gearbox top cover. Owner tried to repair the gearbox himself. During disassembly the gaskets were torn, the gearbox cover mounting studs were damaged, the gearbox housing was broken. Objectively assess their abilities as a mechanic, incorrect disassembly and assembly of the unit increases the cost of subsequent repairs.

Remove the PTO housing, fix the location of gears, washers and stoppers.

Remember the sequence of installation of gears, shafts and gears are fixed by thrust washers, some of which are installed on the shaft, some in the gearbox housing. Some shafts are fixed by needle keys, it is important not to lose them.

We remove the gearshift mechanism, take it off completely, together with its shafts and forks. To do this, unscrew the three nuts and remove the mechanism from the housing.

Shafts and gears of gearbox are visible underneath the gear shift mechanism. The gears and clutch that are marked with red arrows show signs of wear. That’s how the clutches wear out, not only in power tillers and mini tractors, the problem is also typical for old Soviet motorcycles. The ways of solving the problem are also known, someone corrects the clutch teeth with a file or emery, providing a smooth and good hook, someone welds the clutch teeth. This method of repair is justified only when it is not possible to find and buy spare parts. In order to ensure the further flawless and reliable operation of your power tiller the worn gears need to be replaced with new ones.

To remove the shaft with damaged gears, we need to remove the friction clutch. To do this, unscrew the three nuts on the clutch friction, remove the clutch discs. Next, unbend the edges of the locking washer of the primary shaft nut, unscrew the nut and remove the clutch drum. By the way, I like the clutch in this motor-block, powerful discs and easy adjustment, a guarantee of problem-free operation.

Unscrew six nuts and remove the primary shaft.

Unscrew pinion bolt of the intermediate shaft and knock out the intermediate shafts.

Change the gearwheels that are liable to wear and assemble the gearbox in the reverse order. Installing the intermediate shafts.

Install the gearshift mechanism, control that the shift forks exactly hit the clutches.

Replace the gearbox rear cover, put new gaskets, the joints can be sealed with sealant.

Install the primary shaft, clutch drum and assemble the friction clutch. Adjust the clutch. Three nuts on the friction clutch should be screwed on the same number of turns, squeeze the clutch and check that the pressure plate departed from the discs exactly along the plane, if one edge is higher or lower, the clutch will lead. Install engine.

Install new gearbox top cover gasket and install the top cover itself.

Starting the review of the Kadvi MB 90 and its modifications, we would like to mention that these are the first agricultural devices, which began to be produced at the Kaluga engine plant “KaDvi” in the late 90s. Now these modifications are no longer available, however, at one time the line of motor blocks Kadvi MB-90 was very popular among farmers and private landowners.

The manufacturer used to equip the singleaxle tractor with engines of its own production, they were of high reliability, but had a relatively low productivity. Later on, in order to increase the power of agricultural units, the manufacturer decided to switch to foreign engines of higher power, which successfully affected the motor-blocks of later generations (“Ugra” and “Oka”), replacing the MB-90 series.

Faults of CVTs: why the gear starts to fly out?

often than not, in order to get to the place of repair, you can simply not use this gear. Modern multi-stage gearboxes have not a very big gap between stages, allowing to manage without one gear. Yes, and a wide dynamic range of modern injection engine makes it possible to use the crankshaft speed of 1200 to 5500 rpm. It is possible to reach the garage, but the defect should be eliminated.

Causes of transmission dislodgement

Wear of the powertrain mounts. The power unit swings much stronger than it should, and instead of the driver shifting up and down, the gearbox swinging constantly does it automatically. Most often, such defect is in gearboxes with rigid linkage control actuator.

Sometimes a gear disengages in pairs, e.g. second and fourth, because the engagement (and disengagement) direction of these gears coincides. Though it is not always the case: some gears are more worn, others less, and, accordingly, the possibility of gear holding is different. Plus, dynamic jerking in the second gear, for example, is much stronger, than in the fourth.

The treatment is simple. It is necessary to replace the power unit supports. and quickly, because not only the gearbox suffers. From the increased mobility of the unit kinks and can tear pipes, hoses, cables, wiring harnesses that connect the power unit to the other units of the car, and believe me, there are a lot of them.

The drive mechanism is worn. A severely slackened or worn actuator does not allow full engagement of the gear. If it is not fully engaged, it will pop out at the first opportunity. Gears are more prone to kick-out when driving without load (coasting): when the engine revolves the wheels, clutch teeth mesh is much “stronger” than during engine braking. Or as the folks say: “Try pulling a gear under the gas or under a gas release. and you’ll understand everything”.

Clutch. The clutch, on the other hand, can have practically no effect on gear knock-out. When the clutch is not sufficiently depressed, it is very difficult to engage the gear at full speed. But this defect cannot be called a knockout.

Internal defects in the gearbox

The cause of clutch teeth wear can be a malfunction in the clutch or clutch actuator, which prevents the engine flywheel from separating from the transmission intake shaft. Of course, it beats out the gear with damaged gears. often the gear disengages in such situation will be at a sudden acceleration on this gear or intensive braking of engine.

Possible reason for knocking out a gear may be a weakening of the synchronizer springs. You may accurately diagnose this cause only after a complete disassembly of the gearbox.

Gears can also kick out as a result of large axial play of shafts, when the forks simply do not “press” the clutch to the full engaging position. Hence another reason: wear of the forks which causes failure to engage the gear. Gears can also kick out due to severe wear of the gear selector mechanism.

When such a defect as knocking out the gear, you should immediately divide the causes into external, which you can try to diagnose and fix by your own efforts, and the causes of internal. The latter require disassembly and qualified dismantling and inspections of gearbox. So I would recommend to apply to the service, specialists who have already “chiseled a hand” in the repair of these cars, or a specialized firm for repair of the exact transmissions.

Sure, some motorists drive by holding the disengaged gear with their hand, but that’s not the point. You should not procrastinate with the repair, because once the gear is not engaged, it is half the trouble. And it can also jam, and as a result the car will make its way to the service by an evacuator.

Troubles with a power tiller

While operating an engine block, no matter how good it is, sometimes malfunctions occur which disable the block. With proper care and correct operation of the machine you can minimize the risk of these problems and damage. But no matter how carefully you treat your motoblock there are nodes and elements that wear out before others. Undoubtedly, such a node is the engine of the agricultural machine. With the timely troubleshooting of the power tiller you can significantly extend its life.

There are two basic types of problems with the motor block: problems with the motor (engine) and problems with the transmission.

Engine breakdowns. this is the most common problem, because with intensive use of the motoblock, it is this component that does not withstand the load. It is advisable to divide motor faults into two subtypes: faults in which the motor does not start and faults in which the motor does not run correctly.

In case the engine does not start, it is necessary to check all possible faults of the engine of the power tiller, among which the following are the most common:

2.2 Motor position. If it is in a tilted position. you need to place it correctly.

3.Fuel in the engine fuel tank.

4.Checking the Fuel Tank Faucet. The fuel tank may be blocked or clogged. If this is the case, it must be opened or cleaned.

5.Checking the hole in the fuel tank cap. Maybe the opening is blocked and it is blocking the air in.

Fix Your Hydrostatic Transmission Problems Fast

6.Fuel delivery to the carburetor. Check carburetor needle valve.

7.The spark plug does not work. If the spark plug is dirty. it should be cleaned, and in addition, the gap between the electrodes should be measured. Replace defective spark plug.

If the motor of a motorblock starts, but works poorly (malfunctions, does not develop power, stalls), then the possible causes of such malfunctions may be the following:

2.The air filter is dirty. Check the air filter’s condition and clean it correctly according to the filter’s material.

3.Poor fuel quality. If this happens you need to change to the manufacturer’s recommended fuel.

4.The ignition system is broken. Check the spark plug boot as explained before.

5.Muffler clogged with combustion products. Muffler must be disassembled and washed.

6.The carburettor is contaminated. In such a situation it is necessary to remove and clean the carburetor, and then make adjustments according to the instructions of the power tiller.

7.Decreased compression due to wear in the cylinder-piston group.

We have presented the main types of faults of the motoblock, related to the engine. Now let’s take a look at the likely causes of malfunctions in your power tiller transmission:

1.Clutch slipping. This can occur for various reasons. For example: worn friction plates, loose clutch spring, no play between pressure plate and release bearing. If this happens, change the worn discs and springs and adjust the oil slack according to the instructions.

2.Incomplete release of the clutch. Deformed friction plates and incorrect oil in the clutch housing may contribute to this. Replace the deformed discs and fill up with recommended oil.

3.Increased noise in the gearbox. Noise occurs due to the use of low-quality oil or a lack of it in the gearbox. Sometimes the cause is worn gears and bearings. In this case the worn out parts must be replaced.

4.Difficulty shifting gears. The most common cause of this situation is worn parts involved in shifting gears. Here it is necessary to disassemble the gearbox of your power tiller and grind the gears or replace them if there is too much wear.

5.Gearbox oil leakage. Improperly installed oil seals, worn oil seals, clogged oil filler cap breather valve, filling more oil than recommended are all causes of gearbox leakage. 6 5 Difficulty shifting gears, gaskets must be replaced and correctly installed, the breather valve cleaned and the oil level corrected.

6.Increased vibration of the power tiller. This is usually caused by improperly adjusted attachments. It is necessary to tidy up the fixtures or replace them, in case they are worn out.

This article lists the most common types of malfunctions of power tillers, but in practice there is a much greater variety. The first and most important thing you can do to prevent damage is to use your power tool gently, carefully and correctly. My Single Axle Tractor” store offers only quality products that have a warranty and quality certificates. All our products are made of durable, hard-wearing materials and have passed quality control and certification.

Why do I have trouble engaging a reverse gear?

The powertrain enables you to change the engine torque before transmitting it to the drive wheels. This makes it possible to change the speed of the vehicle, keep the engine in the optimal speed range, etc.д.

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

It should be noted that often drivers are faced with a malfunction, when the rear gear is not engaged, and with different types of transmissions (manual transmission, automatic transmission, automatic transmission, etc.).д.). Further we will consider the main reasons why the reverse gear is not engaged in the “mechanics”, as well as in automatic gearboxes.

Rear gear inhibit

The most common problem faced by drivers when shifting gears is a problem with engaging reverse gear.

Not only owners of cars with manual gearboxes can encounter such a problem, but also lovers of “automatics”. With what to start searching and about the possible causes of malfunction we will tell in this article.

Why isn’t reverse gear engaged in a manual transmission??

According to statistics, owners of manual transmission are much more likely to complain about problems with engaging rear gear than owners of cars with automatic transmission. The following are some of the most common reasons for nonengagement or a tight reverse gear engagement

  • Incomplete clutch disengagement. In other words, the gearbox is not disengaged from the engine. Problems with the clutch can make it hard to engage all of the gears, but on some vehicle models, the problem is most noticeable when engaging the reverse gear. Attempting to shift gears with insufficiently depressed clutch is often accompanied by a crunch and loud rattle.
  • Deformation of transmission drive rods or levers. To rule this out, you need to do a thorough inspection of the transmission. Damaged parts need to be replaced.
  • Loss of properties or insufficient transmission fluid level. Most drivers believe that the oil in the transmission is as long as the car itself. Unfortunately this is not the case: the transmission fluid works in harsh conditions and over time loses its performance properties or simply leaks when the unit is not sealed. Problems connected with oil will be reflected in shifting in all gears, not only in reverse. You should periodically check oil level in a box and fill it up / change, if necessary (you may review transmission fluid change intervals in the operation manual of a vehicle).
  • The shift lever is out of adjustment. This problem is well known to owners of front-wheel drive VAZ cars. A badly adjusted rocker makes it impossible to engage the reverse gear or “kick out”. In such a case, there is only one way out. to adjust the cardan of the transmission’s rocker arm.

It is also worth mentioning “special” cars, where the difficulty of engaging the reverse gear is not a breakdown, but a peculiarity of operation. In such cars, it is recommended to overclutch or first engage the first gear before engaging the reverse.

Why isn’t reverse engaged in automatic transmission?

As mentioned earlier, problems with reverse travel can occur not only on the “mechanics”, but also on the “automatics. Here, too, we’ll highlight a few of the most common faults:

  • Insufficient level of transmission fluid or its wear. Automatic Transmission Fluid (ATF). Automatic transmission fluid) is the first thing to check, if you have problems with shifting of automatic transmission. Just like transmission oil, ATF has a certain service life and needs to be changed periodically.
  • Worn friction discs. Depending on the degree of wear, this malfunction may affect not only reverse, but also D mode (the car is driven only in 1-2 gears). Replacing worn friction clutches solves the problem.
  • Sheared splines in the master cylinder. The vehicle moves only forward, and may not respond to accelerator pedal at all. Here only replacement of a drum will help.
  • Wear of friction layer of brake band or corresponding clutch pack (Reverse). When driving forward, the malfunction does not appear, the vehicle simply refuses to move in reverse.
  • Broken or worn brake belt piston seals. As with the previous malfunction, only appears when reversing. One of the valves in the hydraulic unit or the corresponding solenoid is clogged or stuck.
  • Lack of engagement of oil pump pinion with torque converter. Failure of the drive pinion means that all gears cannot be engaged.

Finally we would like to remind you to adhere to the service intervals. Remind your customers of the need for regular maintenance!

if the clutch does not disengage

Our installation tips are for guidance only. This document is a general recommendation. Follow the installation and operating instructions of the vehicle manufacturer as well as the safety instructions and safety regulations contained therein! Work should only be carried out by qualified specialists! Used photo materials and descriptions are of general nature and can differ depending on the manufacturer.


If the clutch will not disengage, this is not always due to a malfunction. Failure of the clutch release system (release bearing, slave cylinder, clutch lever), a blocked support bearing or failure to meet important installation requirements are often the cause of malfunctions in the clutch.

  • Fulfillment of all professional requirements for installing parts. See. SACHS workshop tip: Installing the clutch
  • Wear on clutch release system parts
  • Cables, hydraulics, pivot points
  • Adjustment of equipment

Excessive lateral runout of the slave disc

Set stroke setting is not sufficient for full disengagement.

Always check the slipper side runout prior to installation.

Excessive side run-out of the clutch disc

Excessive side runout of the clutch slave disc

Corrosion on the hub profile

  • Lack of grease or improper grease application during installation
  • Contamination of friction surfaces due to improper transport

Slide of the slave disc over the primary shaft is blocked. The clutch lining is in contact with the friction surface on the flywheel.

Jerking motion is noticeable in the early stages. Use only high-performance lubricants, SACHS 200 080 050.

Friction corrosion on the hub profile

Friction corrosion on the hub profile

Damage to the hub profile

  • During installation, the primary shaft and clutch disc hub were pressed against each other.
  • Excessive angular movement during installation of transmission.

Clutch does not disengage smoothly because the strokes of the idler disc on the primary shaft are blocked.

  • During installation, center the clutch disc with the tools intended for this purpose.
  • Avoid excessive upward, downward or sideways movement of the gearbox during installation.

Bending of the machine disc

  • During installation, the primary shaft was pressed against the hub of the clutch disc.
  • Deformation due to excessive heat (metallic parts turning blue).

Do not disengage the clutch because the intended movement of the pressure plate is insufficient.

Cracks in clutch springs or drive disc

  • Decreasing engine speed or decreasing gear while the primary shaft is in the clutch disc hub will result in cracking due to the lever effect that occurs.
  • Parallel or angular misalignment

Side runout of the drive exceeded

  • Avoid excessive upward, downward or sideways movement of the transmission during installation.
  • Dismantle the gearbox during removal or installation only if the primary shaft is not inside the clutch disc.

Cracks in clutch springs or drive disc

Cracks in the clutch springs or drive disc

Wear / irregularities in the hub profile

  • Clutch housing and crankcase flange are out of alignment, runout due to angular or parallel misalignment
  • Thrust bearing missing
  • The main shaft has too much play or is not guided

This may also cause noise.

Wear / irregularities in the hub profile

Wear / irregularities in the hub profile

Excessive speed: liner tears

  • Driving in a low gear with a high bank angle and depressed clutch pedal, causing the friction disc to exceed the maximum permissible speed and rupture.
  • Shift downshift error (selecting a gear that is too low)

Torn lining particles stuck in flywheel or pressure plate housing.

The problem is not caused by the engine! The speed at which the lining tears exceeds the maximum engine speed. The linings can tear more easily if overheated.

Pads not able to withstand excessive roll angle velocity.

Padding not able to withstand too high an angular roll rate.

Overloading and destruction of the torsion damper

  • Driving with overdrive gear engaged and at low speed and full load
  • Extremely irregular engine operation
  • Worn pivots in transmission

Parts fly out and get stuck in linings.

Torsional damper overloaded and destroyed

Torsional damper overloading and rupture

Tangential leaf spring is bent or deformed

  • Extreme strain due to faulty shifting
  • Incorrect maneuvering during towing
  • Operational errors on the treadmill test rig
  • Backlash in the transmission
  • Deformation during installation
  • Damage during transport

Insufficient free play of pressure plate. Clutch does not disengage fully.

Tangential leaf spring is deformed

Tangential leaf spring is deformed

The diaphragm spring is in contact with the torsion damper when the clutch is released.

  • Permissible actuation range of clutch release clutch exceeded
  • Install incorrect friction disc
  • Drive disc is in the wrong position

Diaphragm spring engages in clutch disc.

Diaphragm spring is in contact with the torsion damper when the clutch is released.

Diaphragm spring in contact with torsion damper when releasing clutch.

Wear on the ends of the diaphragm spring

  • Release bearing preload too low
  • Wear on clutch drive
  • Guide sleeve worn or deformed
  • Engine and gearbox are not properly aligned with respect to one another.

Permanent misalignment between release bearing and diaphragm spring ends exceeds the limits of the self-alignment capability of the components. Relative movement increases wear on all mechanical parts. Clutch does not disengage properly. Same for clutch release levers.

Boring of the diaphragm spring ends

Grinding of diaphragm spring ends

Excessive overheating. cracked pressure plate

  • Constant clutch slipping
  • Insufficient grip force on clutch pressure plate
  • Malfunction of the clutch release system, e.g. increased rigidity
  • Contamination by oil or grease
  • Excessive flywheel thickness

Insufficient freedom of play of the pressure plate.

Severe overheating can cause permanent bending of the pressure plate and result in release problems.

Technical Data

MB-1D products go through a multi-step technical control before leaving the factory. The MB single axle tractor is delivered to the market assembled or packed for shipping.

The Kadvi DM single axle tractor has these specifications:

  • Engine is air-cooled, single-cylinder gasoline;
  • power. 6 l.с.;
  • clutch. pinion, cast-iron gearbox;
  • PTO. 2;
  • number of gears. 3 (neutral, 2 front and 1 rear);
  • tank capacity. 3.6 l;
  • fuel consumption. 1,2-2,0 l/h;
  • Roving speed. 3,5-8,9 km/h;
  • weight of the towed trailer. up to 500 kg;
  • Overall dimensions in working condition (length/height/width). 1500x1150x600 mm;
  • track width. 60 cm;
  • clearance. 14,5 cm;
  • weight with full load. 103 kg.

MB-90m single-axis tractor provides up to 120 cm of grip and 25 cm of ripping depth.

MD-01 series engines are equipped with electronic ignition system and special crank bearings, which increase service life. Innovative box muffler significantly reduces noise.

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