DIY MTZ 80 gearbox repair

In detail: do-it-yourself repair of the MTZ 80 gearbox from a real master for the site my.housecope.com.

The MTZ 80 tractor is a technologically complex agricultural machine, which consists of a number of different systems and units. At the same time, one of the most important elements that ensures the functionality of the machine is the gearbox. This unit is responsible for the operation of equipment in different modes, based on the complexity of the working conditions.

Another important task of the MTZ 80 gearbox is fuel economy during energy-intensive work. In addition, various MTZ 80 transmissions significantly relieve the load from the engine and other components, extending the overall life of the tractor.

The design of the gearbox (gearbox) includes a number of interconnected units. It is during their interaction that the gear is switched to MTZ 80. All the units of the mechanism are assembled in one cast-iron case, the shape of which, in general terms, resembles a cube.

Inside the body there are four steel shafts, each of which is equipped with gears responsible for a particular gear. These shafts include:

The appearance of the MTZ 80 gearbox

All four shafts are placed in pairs, parallel to each other. The upper axis is occupied by the primary and secondary shafts. They are connected to each other through a ball bearing, which is attached to a special groove made in the end face of the secondary axis. In this case, the second end of the input shaft enters the glass, mounted in the housing, and is fixed by the second bearing.

The main task of the primary and secondary shafts is to set in motion the gears mounted on them. There are three of them on the upper axis:

Video (click to play).

two movable presenters: 3rd, 4th and 5th gears;
one fixed driven: reducer pinion.

The remaining intermediate and rear and first speed shafts are installed in the gearbox below the first axle. This axle is fixed with a bushing on the drive gear, which is also recessed into the gearbox housing. In this case, the fixing gear is additionally equipped with a cam, which transfers torque to the power take-off shaft, and an impeller along the edge. The impeller provides a more even distribution of oil inside the gearbox, and is also responsible for engaging the main gear. Both parts of the axle are joined together by another bearing.

Three driven gears are installed on the lower axle in a fixed stationary position. On the extreme gear, one more is installed in engagement - an intermediate one. It connects the outermost driven gear with the driving gear of the 3rd gear. This makes it possible to operate the tractor at reduced speeds. Another additional gear, which meshes with the intermediate gear, provides the reverse gear of the machine. On the far section of the axis there is a movable drive gear of the reducer.

The gear wheel of the second stage of the reducer (driven) is located on the secondary shaft. Here, with the help of a nut, the main drive gear is mounted. The shaft is held on its axis by means of bearings made in the form of a cone.

On the sides of the MTZ 80 gearbox housing, hatches are made that open in case of maintenance or repair of gear units. Also, through these hatches, the power take-off shaft is connected when working with additional equipment. A creeper is also built in here.
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With the help of the gearbox, the MTZ 80 switches between 9 forward speeds and 2 reverse ones. Switching between modes is carried out using a lever from the operator's cab. The lever, in turn, moves one of the movable gears, which, entering the coupling with other gear blocks, engages the gear.In this case, the gearbox operates in two stages of gear shifting.

The first stage is responsible for 1,3,4,5 forward and 1 reverse speeds. This stage is activated when the gear element of the lower axle meshes with one of the rims mounted on the output shaft. When the gear of the intermediate axle moves to the extreme rear position, it engages with the drive gear of the reducer. This turns on the second stage of the box, which is responsible for 2,6,7,9 forward and 2 reverse gears.

Gear selector handle position

Working in the first stage mode, the gear unit can move forward and backward. Moving towards the front edge, it engages the 5th gear. When shifted to the extreme rear position, the 4th gear is included. The main gear of the upper axle also moves. Moving to the forward position, it activates 3 (in the first stage) or 6 (in the second stage) speed. In the extreme rear position, the gear is in contact with the teeth of the second rim of the secondary shaft and includes the main or 9 (in the second stage) gear.

In the event of a forward displacement of the sliding gear, reverse movement is activated (1 or 2 speed - depends on the stage). When the same element is shifted back, the first or second gear is included.

The intermediate gear element is fixed on its own axis. It constantly clings to the driven reverse axle.
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Separate equipment, to which the power of the vehicle's engine is transmitted, is not capable of performing its functions at such speeds. In this case, an additional block is used, which reduces 1 and 2 forward speeds, as well as 1 and 2 reverse speeds of the tractor. This unit is called a creeper.

The creeper is installed on the left side of the gearbox. It consists of a cast-iron body, inside which there is a planetary-type gearbox and several gear units.

When the device is connected to the gearbox, rotation is transmitted from the intermediate gear to the driven gear of reverse gear and first speed. This gear is mounted on the first speed and reverse shaft. The creeper assemblies move the snap ring into the shoulder. In this case, the gear wheel for switching on the device comes out of engagement with the gear wheel of the first and reverse gear.

The gear wheel is connected through the plug with the roller of the control lever of the device. When the lever is moved to the extreme forward position, the fork engages the creeper engagement gear with the intermediate gear element. In this case, the gear of the first gear is disconnected from the shaft of the low gear.

Creeper engagement gear

Steel and cast iron assemblies, as well as their arrangement inside the box, represent a completely reliable structure. All of them are constantly moving and interacting with each other.

As a consequence, all components must be constantly lubricated and regularly serviced. If this point is neglected, the device can quickly fail. Repairs are best carried out by the employees of the service center, but individual malfunctions with the proper skill can be solved independently.
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There can be two reasons for this:

clutch discs used in technology are defective;
gear unit not adjusted correctly.

In this case, the equipment is installed on the repair pit and the defects are eliminated. First of all, the clutch discs are checked for deformation. If the discs are in order, the gears are adjusted.

In this case, first of all, the differential bearings are secured and correctly positioned. After that, the box itself is already regulated. The direct transmission is set and fixed in such a position that the lateral clearances between the teeth of the wheels are located at a distance of 0.18-0.4 mm. Using rubber pads, the driven gears are positioned 40.7 mm from the housing wall.

During rotation, the teeth must touch in length at least 50% of the total length of the tooth.All values are set by installing, appropriately cut, spacers between the gear glass (leading) and the housing. All spacers located must be the same size.

During disassembly of the unit, you must also check the quality of the gears. If one of them shows signs of wear, both the master and the slave are replaced in pairs.

Also, minimal squeaks can occur when the spring in the cam control unit is worn. In this case, the block is disassembled and the length of the spring in the compressed position is checked. This value should be no more than 32 mm. If there is a larger value, it must be changed.
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As a consequence of this phenomenon, the speed is changed without the participation of the operator. There can also be two main reasons here:

strong weakening of the fixing springs;
the shift forks are deformed or worn out.

In any case, it is necessary to disassemble the unit and individually check each of the components. Particular attention should be paid during the inspection to the distance of the throat, as well as the rubbing surfaces of the forks. If the fork or spring is worn out, it cannot be repaired. Replacement is required immediately.
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Knocking inside the transmission occurs when the gears are worn out.

You can solve this problem as follows:

the tractor is put on a jack or on a repair pit;
remove the cover of the transfer case and the side hatch of the switch box;
then one of the wheels is gradually scrolled by hand, while the repairman observes which of the gear wheels is not working correctly;
the device is completely disassembled with the removal of all nodes;
wheels that show signs of deformation or wear are replaced;
the collection of equipment is carried out in the reverse order.

If, in the case of machine operation, extraneous noises are heard from the checkpoint, this indicates wear on the shaft mountings. In this case, the shaft wobbles inside the block and hits the walls and other parts.

To fix the situation, the box is disassembled. Then, with the help of a crowbar, the rigidity of fixing the shaft is checked (it pokes up with an attempt to pull it towards itself). If the axle wobbles, then it is necessary to check the tightness of the fixing nut. If it doesn't help, it's the bearings. They must be removed from the glasses and replaced with new ones.

The gearbox installed on the MTZ - 80 tractors, after the engine, is perhaps one of the most complex tractor units. As with all machines, the MTZ - 80 gearbox is used to select the travel speed, as well as to transfer traction forces from the tractor engine to the wheels. Moreover, the load on the gearbox mechanism is colossal, since the MTZ-80 tractor is designed to move, mainly off-road, with increased and intermittent loads on the transmission. Sharp accelerations, sudden stops, sudden loads especially strongly affect the operation of the gearbox - and all this contributes to increased wear of gearbox parts. Despite the design of the MTZ-80 tractor gearbox and its reliability, confirmed by years of operation in difficult conditions, a time comes when some failures in the operation of the gearbox force repairs. Repairs can be caused by the following symptoms: grinding noise during gear changes, increased noise in the bevel pair of the main gear, tight engagement or spontaneous disengagement of gears during operation. Or there may be just an emergency situation when the checkpoint completely refuses to perform its functions.

To repair the box, the tractor will have to be disassembled, almost all of it. For disassembling the MTZ - 80 tractor and removing the gearbox, jacks, specialized lifters will be needed, on which parts of the tractor frame will be supported during disassembly. Select jacks of appropriate capacity, some of them must be mobile, on casters.
Gearbox repair begins with disassembling the MTZ-80 tractor.
Disconnect clutch housing from transmission.Carefully remove the pins from the holes without bending them. Do not "hammer" the mating surfaces of the housings when they are detached.

The part of the tractor - the engine with the clutch housing remains on the jacks, and the rear part rolls back. Then the jack is installed under the rear axle - and you can disconnect the box, having previously supported it with slings. To do this, you need to remove the box cover, where the screws that secure it to the rear axle are located. Disconnect, too, carefully, pay attention to the pins and mating surfaces.
Wash the box and place it in the place of disassembly.

The check point of the MTZ - 80 tractor consists of a cast iron body, shafts: primary, intermediate, secondary and reverse shaft, as well as a set of gears, bearings, gear shifting mechanism. The gearbox can provide the tractor with 9 steps "forward" and 2 - "backward". In addition, when the reduction gear is turned on, the number of stages becomes twice as large.
The secondary shaft, which has a large axial load from the bevel gear, is fixed in the box housing in tapered bearings. Other shafts are mounted on radial shafts.

After the box is prepared for repair, you need to decide on its volume. If you know a specific part that can be replaced, be it a shift fork or a collapsed bearing, then this is easier - to disassemble the desired unit and replace it. And it's another matter when the general deterioration of the box led to the repair, and it is necessary to completely disassemble and troubleshoot all its parts. A crack in the box body, broken bearing seats or cups in the box body can lead to replacing the box completely with a new one or after overhaul; jammed spline shafts and other defects that cannot be eliminated without additional precise machining.

We insert the secondary shaft, we pass it through the splined hole of the driven gear of the second stage of the reducer.
Due to the small distance between the bearings, fasten tapered roller bearings to the stop. While the output shaft rotates freely, you need to check the torque of its rotation in the bearings. This effort should be 0.7 - 0.8 kgf / m. Tighten the pinion nut until you reach the desired parameters.

To maintain the mounting size of the gearing of the gearbox drive gear with the engine gear, you need to observe the size 58 mm from the end of the gear to the connecting end of the box with an accuracy of 0.15 mm. Tighten the pinion nut with a torque of 20 - 22 kgf / m. If the groove on the nut does not coincide with the hole in the shaft for installing the cotter pin, the nut can only be tightened to the required amount, it must not be loosened. Assemble the countershaft completely by installing all the gears on it.
Tighten the countershaft nut and check the clearance in the gear set. It should be in the range of 0.03 - 0.05 mm.
Having assembled the entire box, check the cleanliness of both mating planes of the gearbox housing, smear them with sealant, stick on new gaskets and assemble alternately with the rear axle housing and the clutch housing.

In any case, it is necessary to entrust the repair of the MTZ 80 tractor gearbox, it is necessary for specialists, otherwise there is a risk of complete failure of the gearbox as a result of its poor-quality repair. In Moscow and the Moscow Region, you can repair the checkpoint at Traktor Service.

The MTZ-80/82 tractor is a technique produced by the Minsk Tractor Plant. This transport is great for agricultural work. The working technique is designed according to the classic scheme: enlarged rear wheels, support system, reliable chassis. The MTZ checkpoint ensures efficient movement of the vehicle at different speed modes. The gearbox of a tractor with MTZ 80 includes several drive stages located on the front and rear axles (9 and 2). It should be noted that MTZ 82 is a modernized version of MTZ-80. Such a tractor is easy to maintain.

The box mounted on the tractor includes securely fixed shafts (primary / secondary).These elements are installed in the box body.

The gears do an excellent job with their inherent functions. On the input shaft there are drive gears of 3 ... 5 speeds. Also, the system includes an intermediate shaft. This element interacts with a 3-speed gear. Changing gears should be carried out at a reduced speed of the power plant, the clutch is squeezed out. Next, the driver sets the required travel mode.

In order to reduce the speed limit on this vehicle, the manufacturer installed the gearbox device with a creeper. It is a gearbox complete with gears. The creeper is present on agricultural vehicles, which are necessary for soil cultivation. A distinctive feature of this unit is that it has an increased working life, small dimensions.

The clutch system guarantees the protection of the existing motor against high loads. Also, the main elements of the MTZ-82 box include the body, the gearshift mechanism. The engine and transmission system are designed for high loads, so they can operate in difficult conditions for a long time. The transfer case belongs to the MTZ 82 tractor engine, which provides the transfer of torque from the gearbox to the cardan drive.

For optimum system performance, fill up to the level of the lower edge of the inspection hole. What oil is recommended for use in KP MTZ 82? Nigrol oil has positive reviews, which has no additives in its composition. This fluid retains its performance characteristics over a wide temperature range and has an optimal viscosity index.

Malfunctions and breakdowns in the gearbox arise both as a result of natural wear and tear of the elements present here, and in the absence of proper care of this system by the driver. In particular, it is not recommended to pull the lever, transferring it from one mode to another.Signs of when the MTZ 80 gearbox needs to be repaired:

large free play of the lever;

difficulty in gear shifting;

extraneous noise from the checkpoint.

The main reason for these signs is the wear of the gearbox components. For any of the listed manifestations of the gearbox on MTZ 80 or 82, it is advisable to carry out a general diagnosis of the transmission system.Transfer case MTZ 82 is subject to periodic maintenance. This procedure includes changing the lubricant. This is necessary to prevent premature wear of the rollers, the driven cage of the freewheel clutch.In some cases, the reason for knocking may lie in the fact that there is a breakdown of the gear teeth. The tractor owner must periodically tighten the screw connections.

Depending on the year of manufacture and equipment, the MTZ-80, 82 tractors can have three types of gearboxes:

with movable gears;
with constant mesh gears (gear shifting under load);
with constant mesh gears (synchronized).

Repair of each Checkpoint has some of its own nuances,
but in general and for the main faults
repair of the check point of the MTZ-80, 82 tractor
performed in the sequence below

1. Remove Check point from the MTZ-80, 82 tractor, install it on the stand, remove the covers and gaskets.

Removing the retaining ring
idler gear
reduction gear

2. Remove: retaining rings, slinger washers; further - removed intermediate gear reduction gear MTZ (located on the inner shaft), slave gear reduction gear MTZ (location - on the primary shaft).

3. Disconnect and press out primary gearbox shaft MTZ-80, 82 assembly, remove the gears from it.

4. Press the pin out of the inner shaft seat, dismantle interior gearbox shaft MTZ.

5. Remove the retaining wire, unscrew the set screw, take out the shaft of the reducer switch; dismantled MTZ reducer switch fork

Pressing out the inner shaft

6. Disconnection and dismantling of the ball bearing cup of the drive gear of the II stage of the reducer assembly. Remove the front ball bearing seat of the inner shaft assembly.

7. Dismantle the inner shaft, remove the gears and thrust washer.

8. Disconnect and remove the strip and thrust washer. Squeeze out shaft 1st gear and rear shaft stroke MTZ gearbox... Take off bearing and slide gear, remove the shaft.

9. The nut is removed and leading gear from the secondary shaft MTZ. Dismantle the output shaft sleeve. Take off adjusting gaskets and take out secondary gearbox shaft MTZ-80, 82; remove the gear, spring disc and spacer sleeve from it. Pressing the ball bearing out of the shaft gear.

10. Washing and drying of parts. Defect detection details Check point MTZ-80, 82 performed according to special tables.

11. If necessary, disassemble: primary shaft, secondary shaft of MTZ-80, 82 gearbox.

12. If the condition of parts such as: gears of the primary shaft of the MTZ gearbox, gears of the secondary shaft of the MTZ gearbox, gear of the reduction gear of the MTZ gearbox, driven gear of the MTZ gearbox, bushings, rods, gear shift lever MTZ checkpoint does not meet technical requirements, and cannot be restored - they are replaced with new ones.

Assembling the gearbox of the MTZ-80, 82 tractor performed in the reverse order of disassembly.

The bearing seats are lubricated with oil. Bearings Check point MTZ-80, 82 pressed against the stop.

If transmission case MTZ-80, 82 has cracks - they are welded.

Adjustment of the check point of the MTZ-80, 82 tractor

1. Set distance from the end of the drive gear to the gearbox housing 58 ± 0.15 mm.

2. Tapered roller bearings of the output shaft adjust with interference.

3. Moment of resistance the rotation of the secondary shaft in the bearings (not taking into account the engaging gears) should be kept within the limits of 0.7 - 0.8 kgf.m.

Checkpoint took off where to start without knowing the way to me this tell me

for what purpose were they removed?
what flew?

to disassemble it is necessary
from the clutch side, remove the upper gear of the reduction gear and the lower (preferably a puller),
remove the upper spline shaft, which enters the secondary
with a puller, remove the bearing from the lower support of the tubular shaft 212
there is a hole under it, knock out the spring pin of the VOM shaft, then remove it from the side of attachment to the bridge
from the side of the rear axle, remove the support of the lower shaft (tubular)
from the clutch side, unscrew the tubular shaft nut and remove it towards the axle
then remove the secondary shaft, the intermediate shaft will interfere, you will have to move it a little

Thank you for the detailed answer The bearing on the shaft that goes to the PTO collapsed, I had to disassemble everything, it turned out that the gears were worn out, everything means the gearbox to remove the gearbox worked fine under load rarely flies 1 low, did not decide to change the gears in the gearbox or not, tell me.

so you, in order to change the bearing that collapsed and you do not need to completely disassemble the gearbox
remove the PTO shaft and you can remove this cover
gears in appearance are not so bad, there are no broken teeth
the transmission may have flown out due to backlash in the bearings, then the bearings for replacement
Is there a cotter pin on the shank nut?

Thank you, the cotter pin is in place, I will put the impeller bearing, today I will put the gearbox

the gear wheel of the first and reverse gear sliding is worn out by half dismantled so do it again after three years

Today I disassembled the gearbox I will replace 4 gears 1 bearing

Good afternoon! Tell me, is it possible to replace the intermediate reverse gear in the MTZ 82.1 checkpoint (eaten up + the half-tooth fell off) through the hatches, or just remove the box? Thanks in advance.

I won't say for sure
but you need to roll out the gearbox from the clutch housing, the gearbox from the bridge may not have to be removed
maybe even more experienced ones will tell you

The gearbox will have to be rolled out from the bridge, it is not necessary to disconnect the gear, if the shaft and other gears do not interfere, then it can be obtained by removing the gearbox cover and the shift forks. The shaft is fixed with a plate with 2 twisted bolts from the side of the basket in the right corner at the bottom. I will attach a few photos, the gear from the probe side at the bottom.

Then I will completely remove the checkpoint, at the same time I will look at the bridge (I read it here, you can move it back along the frame, EO2101). Thanks for answers!

Good day! Help with advice, six months ago MTZ-82 in the 9th gear the sound appeared bad, they did not use the 99th yet, now in the 6th gear there is something similar, that is, on the same shaft. (took the new year three ago, with a large front axle)
Is it possible to look into the checkpoint without removing the cab. Has anyone come across such a thing, and can such a thing “break the wood” if it is not possible to make out now? I understood that it would be necessary to remove the cockpit when halved.
Thanks in advance for your answers.

Tractor driver 74, try to remove the VOM razdatka from the checkpoint on the right side of the left cover with a probe, pull the bridge so that the wheel spins, maybe you will see something through the hatches.

tractor driver 74 remove the polic and the gearbox cover can be seen there and your shank has unscrewed

Thanks for answers,
if the shank is unscrewed, can it be tucked through the hatches, or will you still have to half the tractor?

can be pulled up and welded through the rear axle hatch

opened the hatch with the probe,
there is what
1, ninth included
2, neutral
3, sixth
dad all his life on tractors and in bewilderment, but the MTZ engines were capitalized, but the clutch was changed, BUT the gearbox. only the oil was checked !!
What happened, the parts are raw? and where to get good ones?

We all have another reason for MTZ players - we mainly use 6,8,9th gears (third, fifth) IN the photo, as if the 7th was not included. And the spare parts are probably all the same. O. Crankshaft on t-150 soviet we cannot find one china and india

..it means they drove the tractor for disassembly, dropped into the gear store, said yes, everything is in stock, both China and Belarus (good familiar sellers),. And China I say who is purposefully taking - who cooks for sale, they answer.
So you want to say forget the problem with the box - they show the box of the Soviets at the time, we will give it back for 40 tons,
lever only without wings (straight).
A question for connoisseurs - will there be an ambush with a drive on my MTZ 82 large front axle, logically I understand that everything should be the same, but experience says that anything and everything can happen ..

so what is easier, count the teeth on the drive gear of the secondary shaft on your own and store gearbox and everything will become clear.

And so I threw off the box and now I need the help of experts in this matter. Tractor MTZ - 80. How to disassemble and assemble it correctly? I have never made a tractor. The reason for the disassembly, The tractor drove back with a crunch and hummed terribly .. The feeling was that something jumped over the teeth. Zero in the box. At the moment, I'm waiting for advice so that later I don't repent and don't buy too much. Who disassembled the boxes forgive advice. Is it possible to simply disassemble or where do the labels need to be left?

The box is disassembled. A lot of things that are unusable, and at the same time, someone has already done repairs before me. Reason The bearing collapsed. I'll post the photo later in the blog, probably. And a lot of gears you need to change three or four pieces.

look at the topic “full capital of the MTZ82 tractor.” in it, the owner of the topic took pictures of everything in detail and laid it out for everyone's benefit, so that everyone could use it, there are enough tips, the topic has not been visited for a long time, but it should be somewhere nearby in the RTM.

tell me the MTZ82 engine works with a light knock, as if early ignition at high revs is all right,
the ignition shifted. I looked at the clearance in the valves, the pump and injectors, too, I can’t understand the power slightly weaker than the norm

assembled your tractor
-the 6th gear gear was replaced
- the tapered bearing of the front axle drive gear is slightly tightened
the gears are good, the shank is in place, the bearings are ok
verdict - it was possible to drive, grazing and spalling happened in engagement with a lazy gear, not responsible for the drive (it's also a mystery to me), of course, lubrication would be worse
I took pictures of the collapsed tractor (several) if interested, who will post it
thanks everyone for the advice

if interested, who will post it
thanks everyone for the advice

Upload pictures for general vision, maybe someone will come in handy.

Hello to all mtzists, I bought a repair pvm, it looks like everything is fine, but the rattle rattles and howls a lot

, the machine itself in the razdatka staggers a little, like on bearings, but it is clear that the repair was done, the shaft does not play. maybe it's still in the gaskets on the razdatka clamping the gear? There is no desire and time to disassemble the handout once again. My opinion is that there is nothing to play at all, it should not stagger and dangle! Write the answer in a personal

otherwise I'll lose ..

Video (click to play).

Hello everyone, the parts are a little raw and have patience when shifting gears - don't shuffle the speeds! Then you won't have such wear and tear for a long time! Try not to put a lot of raw Ukrainian bearings like plasticine! The gears themselves are normal but well worn, so that the gears can be easily turned on, you can sharpen everything sideways during repairs! No need to find fault with me, it was not me who invented it, but the repair shops!