24.02.2009
Properties and application of oils for hydromechanical transmissions
Oils for hydromechanical transmissions
used in torque converters and automatic transmissions trucks and buses domestic production; in quarry, road, construction and other large-sized equipment, which require oils for hydrodynamic transmissions, as well as in hydrostatic drives of self-propelled agricultural and other equipment
The main purpose of Hydromechanical Transmissions (HMT)- ensuring a change in torque and wheel speed in value and direction, without interrupting the power flow when changing gears.
Hydromechanical transmissions, their advantages and disadvantages
Advantages over mechanical transmissions:Main functions of hydromechanical gear oil
Oil -
The torque converter performs the following functions:
1 - input shaft;
2 - planetary input gearbox;
3 - torque converter;
4 - planetary output gearbox;
5 - output shaft;
6 - oil pump;
7 - heat exchanger
Hydrostatic drive (Hydrostatic drive)
The use of a hydrostatic drive simplifies the construction power transmission, abandon such traditional transmission units as torque converter, gearbox, main gear, brake mechanisms.
The diesel engine 1 drives two separate, identical and independent reversible hydraulic pumps 3, which are connected by high-pressure hoses 4 directly to the reversible hydraulic motors 5.
Basic properties of oils for hydromechanical gears
Hydraulic oils must provide:
Oil for hydromechanical gears Grade “A”
Oil grade "A" intended for all-season operation in torque converters and automatic transmissions of domestically produced trucks and buses. It can also be used in hydrostatic drives of self-propelled agricultural and other equipment.
Contains an effective additive composition that provides high level operational properties of the oil. Protects hydraulic drive parts from corrosion, has good filterability and anti-foam properties.
A high viscosity index ensures stability of viscosity-temperature characteristics over the entire operating temperature range. Good dispersing properties and chemical stability prevent the formation of sediments and varnish deposits on the surfaces of hydraulic system parts
Application area: Hydrodynamic transmissions tractors produced by JSC Petersburg tractor plant", JSC "PROMTRAKTOR" and other large-sized quarry, road, construction equipment where oils for hydrodynamic transmissions are required.
Oil for hydromechanical gears grade “P”
Oil grade "R" - hydraulic oil, designed for all-season use in power steering systems and hydrostatic transmissions. Contains an effective additive composition that ensures a high level of oil performance properties. Namely, good anti-corrosion, anti-foam, dispersing properties and high chemical stability ensure protection of system components, prevent the formation of sediments and varnish deposits on the surfaces of hydraulic system parts
Main Application:
Power steering for KAMAZ, MAZ vehicles, LiAZ, LAZ buses, etc. Hydrostatic transmissions ( Hydrostatic transmissions) loaders, asphalt pavers
MGE oil – 46B
The oil is intended for hydraulic systems (hydrostatic drive) of agricultural and other special equipment, operating at pressures up to 35 MPa with a short-term increase to 42 MPa. Contains an effective additive complex that ensures a high level and stability of viscosity, anti-wear, and antioxidant properties.
The oil is not aggressive towards materials used in the hydraulic drive.
Application area:
IN hydrostatic drive: agricultural machinery produced by the company "ROSSELMASH", in hydraulic systems agricultural equipment.
When the correct oil is poured into the transmission in a timely manner, it can effectively prevent wear on the surfaces of transmission components. In addition, changing the oil prevents scuffing and welding of metal parts to each other, thus minimizing the risk of destabilizing normal operation. And if the question of periodically changing the oil in a manual transmission disappears by itself, the only question that remains is the choice: what kind of oil to pour into a manual transmission.
A manual transmission consists of hundreds of miniature mechanisms that ensure the correct functioning of the entire system only through smooth interaction and uninterrupted operation each unit. However, since many coatings of such mechanisms have an uneven surface, grooved with special small teeth for engagement with the same parts, they Full time job at high temperatures can cause the teeth to lose their strength properties and wear out. When the coatings of such spare parts lose their texture, the connection with the remaining mechanisms can be broken at any second, and this can lead to all sorts of consequences, including the need to replace the gearbox itself. This is why you need to choose the right oil for manual transmission. Oil is a viscous substance that, when it gets on any part of the box, envelops it and forms a protective film. Such protection in itself does not in any way affect the characteristics of the mechanisms that relate to their strength, but due to its properties, the oil film provides smoother adhesion of several surfaces so that damage does not appear on these surfaces as a result of their interaction - scuffing.
Of course, without scuffing, all parts will last much longer, relieving the car owner of the need for such a labor-intensive procedure as dismantling the gearbox to replace them. Oil in mechanical box transmission is similar in purpose to the purpose of motor oil, so many, especially novice car owners, are often interested in whether oil intended for internal combustion engines can be poured into mechanics. Even the representatives themselves do not give a definite answer official dealers, however, according to their recommendations, engine oil can still be poured into a manual transmission, but only in one case: when the engine torque is completely transmitted only to the front wheel axle, i.e. for vehicles equipped with front-wheel drive. They explain this possibility by the arrangement of gears in the mechanical boxes of front-wheel drive cars, which are shaped like small cylinders. The clear difference between gearbox oil and motor oil is mainly in the degree of viscosity - the version for internal combustion engines will be more liquid and fluid. However, before pouring engine oil into the box, you should carefully check whether such an alternative is allowed specifications car. Yes, the price range of motor oils is more affordable than similar fluids for manual transmissions, but if the oil is not suitable, there is a risk of failure of the entire gearbox, and such repairs will be many times more expensive. It is necessary to clarify such points exclusively with official representatives the company that produces such cars, and it is recommended to carry out oil changes from them with the possibility of obtaining a guarantee.
PROPERTIES OF OILS FOR MANUAL TRANSMISSIONS
Of course, the most significant criterion when choosing a fluid for a manual transmission is the degree of viscosity, which is always indicated by the manufacturer on the label. In addition to viscosity, there are some other important characteristics such oils - operational properties. The oil that has each specific property is marked on the label as follows:
- GL-1 – mineral-based gearbox oil, without additives;
- GL-2 – oil consists of elements with a high percentage of fat content;
- GL-3 – oil contains special additives to protect box elements from scuffing;
- GL-4 – oil containing a whole complex of additives: anti-scuffing, reducing wear, etc.;
- GL-5 - marking has a meaning similar to the previous one, the difference is in the quantity and characteristics of additives.
Oils with the first three markings are intended mostly for cars older than 10-15 years old, equipped with a manual transmission. Fluids with “GL-4” and “GL-5” properties are by their nature more universal and can be used for a larger number of vehicles, but it would be preferable to use such oils for passenger transport with manual transmission.
IMPORTANT: what kind of oil to pour into a manual transmission: “GL-4” or “GL-5” - oils marked “GL-4” are intended exclusively for transmissions of cars equipped with front-wheel drive, while “GL-5” is used for manual transmissions for rear-wheel drive versions and for axles. If the oil is equally suitable for machines with any drive arrangement, two markings are placed on the label next to each other. Oils designated as “GL-6” are also commercially available, but in practice they are not used as often, because “GL-5” is officially recognized more high standard quality.
SELECTION OF OIL FOR A MANUAL TRANSMISSION BY VISCOSITY DEGREE
As a rule, the first thing a consumer pays attention to when choosing oil, regardless of whether it is intended for an internal combustion engine or a gearbox, is the alphanumeric designation on the bottle label. This indicator is a determinant of oil viscosity. In the indicated inscriptions, the symbol “W” stands for “winter”, which literally means “winter”, and the designations in the form of numbers show the relationship to the season of use of the liquid in winter time of the year. If the “W” symbol is absent in the inscription, the oil is preferable for use in the spring-summer period with a higher constant temperature regime. Designations for the degree of viscosity of oils for manual transmissions are presented in table form: Class Temperature, at which the viscosity does not exceed 150,000 cP oC Kinematic viscosity at a value of 100 °C, cSt min max 70-W — 55 4.1 — 75-W — 40 4.1 — 80-W — 26 7.0 — 85-W — 12 11.0 — 90 — 13.5 24.0 140 — 24.0 41 ,0 250 — 41.0 — * the symbol “-” means that the oil is unsuitable for use under the specified conditions or with similar parameters.
Numerous tests show that, for the most part, one-season oil, which is intended for vehicle use only under specific weather conditions, does not fulfill the full potential set by the manufacturer. So it's permanent replacement is often impractical unless we are talking about sports car with a very capricious box.
In order to save themselves from the need to change the oil with the onset of each new season, many motorists prefer to pour all-season fluid into the box. All-season oils are labeled, for example, “80-W-90”.
CHECKING THE OIL LEVEL IN THE MANUAL TRANSMISSION
In order to change the transmission oil in a timely manner, you need to periodically monitor its level. Checking the oil level in the manual transmission is as follows:
- the crankcase surrounding the manual transmission drain hole must be cleaned;
- open the plug that blocks the oil drain hole using a wrench.
IMPORTANT: checking the oil level in the manual transmission should only be done when the transmission itself has completely cooled down from operating temperatures, i.e. no less than a few hours after the last car trip. After carrying out all of the above procedures, provided that the oil level is okay, it should begin to ooze through the hole. Otherwise, you need to try to feel the insides behind the walls with your finger - the oil level in the manual transmission should not fall lower than the lowest edge drain hole.
PROCEDURE FOR CHANGING FLUID IN A MANUAL TRANSMISSION
So, if preliminary diagnostics have revealed such a need, the oil in mechanical transmission need to replace. How this procedure works:
- Through the drain hole, all the liquid in the box is completely drained into any container. It is necessary to wait until all the old oil is drained to prevent mixing of old used additives with new ones;
- new liquid is poured into the box using an elastic tube or a large-volume medical syringe (more than 16 cubic meters). This method of filling is due to the inconvenient location of the drain hole. Filling is carried out until the oil level in the box exceeds the level at which the lower edge is located. It must be said that the mixture of old and new fluid will happen one way or another, but to a small extent. For those who want to pre-flush the contents of the manual transmission from old oil, the best solution is to contact the center service, specializing in this type of work.
ADDITIVES FOR TRANSMISSION OILS FOR MANUAL TRANSMISSIONS
In some types of gearbox oils, additives are already added to the composition by the manufacturer. The additives themselves are diluting components for automotive fluids, which improve their properties and help lubricated parts last even longer, protecting them from wear. In cases where it is necessary to extend the life of a car without changing the oil on a manual transmission, you can add separately sold additives to it. Thanks to their use, gears will shift smoother than before, because the teeth on the surfaces of the mechanisms will be lubricated even more efficiently and will move through their radius more smoothly. Thus, the use of additives in oils increases the coefficient useful action the box itself. Additives are added to the main liquid in a ratio of 15-20 ml/2 l. Adding additives allows you to obtain the following benefits in the future:
- improvement of characteristics responsible for the speed and smoothness of gear shifting;
- improving sound insulation of box surfaces;
IMPORTANT: the use of additives for oils that are poured into damaged manual transmissions or transmissions with a high degree of wear is not recommended by manufacturers.
CONCLUSION
As a result, the choice of oil for manual transmission occurs according to several criteria:
- the age of the car and its technical condition, in particular – the condition of the manual transmission;
- car wheel drive;
- temperature conditions and conditions in which the car will be operated.
The choice of manufacturer should be made by car owners individually, based on the advantages and disadvantages of each of them. Timely oil changes will guarantee stable and efficient work for manual transmission of any car.
The abbreviation CV joint is an abbreviation for the phrase “joint of equals.” angular velocities" IN cardan shafts rear wheel drive cars Similar functions are performed by hinges consisting of a crosspiece and cups with needle bearings. The only difference between them is that the cross provides a much smaller degree of freedom than the CV joint. But the cheapest CV joint is much more expensive than the most expensive spider. This circumstance increases the desire to extend its service life. For which, of course, you can use good lubricant and monitor the condition of the boot. Therefore, the question is what best lubricant for CV joints, it is natural. Timely replacement of a torn boot will also extend the life of the grenade if the lubricant is changed at the same time.
CV joint design
At the beginning of the last century, many CV joint designs were developed, which are used to this day. For example, cracker or cam, cam-disk, ball with dividing grooves or with dividing levers, with spherical rollers and a fork, paired cardan shafts. All CV joints have both advantages and disadvantages. The performance of each design is better for some conditions and not so good for others. Therefore, there is no question which design is more successful.
For external joints of modern fast drives passenger cars mobile phones turned out to be better characteristics ball joint with 6 balls. The CV joint body and the inner ring under the separator, which keeps the balls from falling out of the CV joint, have the same number of grooves for them. The connection of the inner ring with the drive and the CV joint housing with the hub is splined. At large angles of rotation of the drive wheels, the maximum permissible torque transmitted by the hinge is much less than at small angles. Therefore, for long-term trouble-free operation of the CV joint, it is necessary to prevent it from working with a heavy load in the extreme positions of the steering wheel. Each CV joint is necessarily protected by a boot.
Tripoids are often used as internal grenades. They are less mobile, but more wear-resistant, since needle bearings are used in their design. 
Lubricant composition for CV joints
For modern ball CV joints, grease is used lithium grease, most often based on mineral oils containing molybdenum disulfide as antifriction additive(from 3 to 5%). Due to its black color it can be confused with graphite lubricant, which under no circumstances should be used in CV joints. Due to its weak anti-friction qualities, regular lithol cannot be used to lubricate CV joints either.
For tripoids, you cannot use the lubricant described above. They can only be used special lubricant barium based. One of its differences is the wide temperature range in which it can operate. After all, in winter the drive cools down to -30, and in summer it heats up to +160 ○ C.
Greases are made by thickening the base oil with various thickeners, which can be salts of higher carboxylic acids: lithium, calcium, aluminum, sodium and others. Inorganic thickeners, such as bentonite clay, as well as synthetic ones, for example, polytetrafluoroethylene, can also be used. As a rule, the lubricant contains up to 90% base oil, the remaining 10% comes from the thickener and various additives that determine the main characteristics of the substance.
In what cases does the CV joint lubricant change?
If the drive is crunchy, it is too late to change the lubricant in it. The drive itself needs to be replaced. This is explained by the fact that if the hinge crunches, it means that it already has significant wear and no matter how much you change the lubricant in it, it will not get any better. To determine which of the joints has crackled, you need to select a flat asphalt area and drive along it, turning the steering wheel all the way to the left, and then all the way to the right. At this time, the assistant, being outside the car, must evaluate in which case the crunch is louder. If the sound is louder when the steering wheel is turned to the left, then the left outer drive needs to be replaced. When the crunch is louder with the wheels turned to the right, you need to change the right outer drive.
How to properly change the lubricant in CV joints
Correct lubricant replacement. Replacing the lubricant in CV joints is done due to its contamination after the boot ruptures or its service life expires when it contains a lot of wear products. It is necessary to completely remove the old grease from the joint to eliminate the possibility of increased wear of the CV joint. To do this, it should be disassembled and thoroughly wiped with a clean rag. It will not be possible to wash it without disassembling it, because the grease is extremely difficult to wash off.
Retaining ring
With disassembly internal hinge Usually there are no difficulties, so we will describe disassembling the external one. If you do not have a special tool for removing the outer hinge, then remove the drive assembly and clamp it in a vice. Remove the clamps from the boot. When removing, try not to damage them; the factory ones are usually better than those that come with the new boot. If the cover is torn, cut it off with a knife; if not, slide it onto the drive rod. Use a hammer to knock the joint off the drive using a drift on the inner ring. Turn the inner ring with the separator so that the holes in the separator are visible, and the symmetry axes of the separator and the housing will be perpendicular. Using a flathead screwdriver, remove all the balls from the separator. In the separator, two of the six holes are longer than the others. Turn the separator so that they are pressed against the walls of the housing and remove the separator with the inner ring from the housing. After adjusting the position of the inner ring, remove it from the separator. Remove any remaining grease from the parts as best you can, and the hinge can be assembled.
Insert the inner ring into the cage. Orient the cage so that the long holes in it are pressed against the hinge body, and insert the cage and ring into the body. Insert the balls into the holes of the separator and rotate the inner ring so that the hole for the drive is located along the axis of the housing. The unit requires from 120 to 150 g of lubricant. How much will fit in your case depends on the size of the hinge.
To properly fill the joint with lubricant, clamp it in a vice with the drive hole facing up. If you bought the lubricant for it in tubes, then press it into the hole under the drive, pressing the tube more tightly to the ring, until it appears between the separator and the housing. If you have it in a different package, then put it on with a spoon and press it into the hole for the drive with a cylindrical object of suitable diameter; The filling criterion is the same.
When installing the boot, do not put a lot of grease into it, otherwise it will tear it apart while the boot is working. Before tightening the boot clamps, lubricate the grooves for them with lithol.
Lubricant testing
The tests included the following checks:
- Rinse with water and protect the unit from penetration of this liquid into it.
- Fluidity when temperature rises to 180 ○ C.
- Lubricating properties.
- Resistance of the lubricating film to pressure.
- Wear of metals protected by lubricant.
Places during the testing process were not allocated to the competitors, they were simply graded, so you will have to determine which lubricant is better. Below are the test results greases for ball joints by one of the independent researchers.
Properly lubricate the tripod joint
Despite the fact that the design of the tripoid joint is based on the use of needle bearings, lubricating them with 158 grease, which is usually used for needle bearings, is strictly prohibited. The fact is that a lithium thickener is used for its manufacture, and it can work at a temperature no higher than 120 ○ C, and the temperature internal grenade reaches 160 ○ C. Since the lubricant for the internal grenade is quite liquid, it is better to pour it inside the boot installed on the drive, and then assemble the tripoid. You need to fill in from 100 to 130 g of lubricant. More precisely, to the question, “how much?” the manufacturer will answer.
Each transmission has gears mounted on shafts. They rotate due to bearings, which, along with the meshing gears, require regular lubrication. It is necessary to select oil taking into account the operating conditions for the rubbing pairs. And here the question arises: which oil is better for a VAZ gearbox? For most motorists, it is no secret that helical gears are used in gearboxes cylindrical gears, in which two gears have teeth in contact with each other. This contact has a plane-fixed nature, that is, when two teeth mesh, they become stationary relative to each other.
This is the main difference between them and hypoid transmissions, in which the contact is point. Due to certain design features they experience longitudinal sliding of the teeth, causing strong contact stresses and significantly worsening lubrication conditions.
Oils for hypoid gearboxes
Serious specific pressures and significant longitudinal slip cause destruction of the oil film in the contact zone, and this can contribute to the metal of the rubbing surfaces seizing. This disadvantage Hypoid gearboxes are usually eliminated by using high-viscosity oils with special additives that ensure sufficient oil film strength. The gears also receive additional phosphating.
Classification of oils
According to the international system API transmission Oils are divided into several categories:
- GL-1 - SAE 75W. These oils are suitable for spur, worm, and bevel gears operating at pressures up to 1600 MPa and temperatures not exceeding 90 degrees.
- GL-2 - SAE 80W/85W. Suitable for spur and spiral bevel gears. They operate at pressures up to 2100 MPa and temperatures up to 120 degrees.
- GL-3 - SAE 90 - similar to the previous one, but withstands up to 2500 MPa and up to 120 degrees.
- GL-4 – SAE 140. Designed for various transmissions, including hypoid ones with operating pressures up to 3000 MPa and temperatures up to 150 degrees.
- GL-5 – SAE 250. Designed for hypoid gears with pressures over 3000 MPa and temperatures over 180 degrees.
- GL-6 – applicable with hypoid gears working in harsh operating conditions. The oil contains particularly effective anti-wear and extreme pressure additives.
Oil designed for VAZ oil is suitable for front-wheel drive vehicles. Typically, lubricants of classes GL-3 or GL-4 are poured into such boxes.
Engine oil in a VAZ box
Some car owners do not understand where the recommendation for pouring motor oils into the transmissions of VAZ cars came from. The fact is that motor oils By operational characteristics refer to GL-1 or GL-2. When the automaker began producing the first cars in 1984 front wheel drive VAZ 2108, there was not enough volume in the USSR suitable oils, satisfying the necessary properties. The most popular for passenger cars at that time were the M5z, M6z, M8z motors, as well as the TAD-17 transmission, which was later replaced by the TAD-17I. The last two meet the requirements of group GL-5.
Consequently, motorists chose the lesser of two evils. Too viscous oil in larger volume boxes caused high loads, affecting the synchronizers and causing significant mechanical losses in cold weather.
First fill oils
New types of oils, including imported ones, gradually appeared, and the recommendations of automakers changed. The plant itself began to introduce oil into the box of vases in the assembly production for the first fill of TM 5-9P.
This oil is filled only at the factory, and it is not available for sale. According to the automaker's recommendations, this lubricant in front-wheel drive gearboxes must be changed after 75 thousand kilometers. On classics and all-wheel drive VAZs, this oil is changed after running in, that is, after 2-3 thousand kilometers.
Oils for VAZ 08-099 gearboxes of the following brands are available for sale:
- TSp-10 (TM-3-9),
- TSp-15k (TM-3-18),
- Tap-15v (TM-3-18),
- TSz-9gip (TM-4-9z),
- "Rexol T" SAE 80W-85 API GL-4,
- "Volnez TM 5-12".
As for imported transmission fluids, almost any lubricant that meets the GL-3 and GL-4 classifications can be used.
Viscosity selection
The use of domestic transmission oils for VAZ, many of which today belong to API class GL-5, promotes accelerated wear of synchronizers. In this regard, it is better to fill the transmission of front-wheel drive cars with API GL-4 or API GL-4/5 fluids with the following viscosity:
- SAE 75W-80,
- SAE 80W-85,
- SAE 80W-90.
Domestic GL-4 oil is not easy to find and is often an expensive semi-synthetic or synthetic product. It is better to buy imported fluids, the use of which helps extend the life of the car transmission. Read how to change the oil in a VAZ gearbox in a separate article on our website.
There is no need to fill high-viscosity VAZ gearboxes with oil, including 5W-50 and 10W-50 engine oils, as well as 85W-90 transmission oils. The higher the viscosity, the stronger the oil film and the less easily the oil penetrates the elements of the box. Too much high viscosity contributes to the difficulty of synchronizer operation, since excess oil must be squeezed out. The automaker VAZ recommends TM-4-12 fluid with a viscosity of SAE 80W-85. The main thing is to find an original on sale, not a fake.
The answer to the question of what kind of oil to pour into a manual transmission is still far from clear for many motorists, despite all its importance for normal use car.
Meanwhile, the reliability and durability of the manual transmission largely depends on the correctness of the answer. After all transmission lubricants- this is something that can significantly “facilitate” the operation of the box units, which have to be constantly subjected to high loads and other technical difficulties.
The reliability and durability of the manual transmission depends on the correct choice of oil.
Functional purpose of lubricant for “mechanics”
In any mechanical car box gears, there are many different gears, the toothed surfaces of which are constantly in dynamic contact with each other. All gears are mounted on shafts, the rotation of which is ensured by the normal functioning of various bearings.
The oil protects the manual transmission from premature wear.
Gears gradually wear out when interacting with each other, and shafts with bearings are also subject to wear due to friction. Transmission fluids can increase the coefficient of sliding that resists friction and impact forces.
High-quality materials effectively lubricate rubbing parts and reduce mechanical stress on parts. In addition, they carry out other important additional functions: perform heat removal from overheated components, remove pollution, metal and other impurities, clean metal surfaces from corrosion.
It must be borne in mind that the oil for a manual transmission has to perform its functions in very difficult conditions: under high pressure and with increased longitudinal sliding. But even under such conditions, in order to optimally perform its main tasks, the gearbox oil must constantly remain in the active friction zone. Thus, it must meet certain parameters.
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Types of transmission fluids
The first significant division of oils for manual transmissions- This is a division according to the type of materials on the basis of which they are created. Like engine fluids, transmission fluids are divided into the following groups:
IN technical passport car indicates what type of oil should be used for this brand.
- Oils on mineral based. They are among the most common and actively used lubricants. Their main component is substances made from natural minerals. They gained their popularity among car owners primarily due to their relative cheapness. At the same time, mineral oils are inferior in quality to semi-synthetic and, to an even greater extent, synthetic lubricants.
- Semi-synthetic based oils. This variety lubricants according to its qualitative characteristics it is approximately in the middle between mineral and synthetic oils. Combined, hybrid “semi-synthetics”, on the one hand, “works” better in a number of parameters than its mineral counterparts, but on the other hand, it costs less than high-quality synthetic gear oils.
- Synthetic based oils. Lubricants This category has improved parameters compared to mineral water. This primarily concerns such characteristics as fluidity and the dependence of oil thickness on temperature conditions. Compared with mineral oils“synthetics” are characterized by better fluidity. True, for cars with high mileage And increased wear this property may also have Negative consequences(for example, when oil leaks through the gearbox seals). In addition, the nominal density of “synthetics” allows it to be used at severe frost, as well as with significant temperature fluctuations.
Division of oils for manual transmissions by viscosity degree
Viscosity is a characteristic of gearbox oil, which indicates the temperature limits of normal operation of the fluid.
This parameter for transmission fluids is similar to the corresponding division of motor oils.
The division of all oils into viscosity classes was developed by the American Association of Automotive Engineers. Based on the first letters of the English name (Society of Automotive Engineers), the corresponding standard received its abbreviation - SAE.
Standard SAE viscosity shares everything transmission oils into three large groups:
- winter (for example, SAE 0W, 5W, 10W, 15W, 20W, 25W), where the letter W (from the word winter) means “winter” grade;
- summer (for example, SAE 20, 30, 40, 50, 60);
- all-season (for example, SAE 0W-30, 5W-40, 10W-40, 20W-50, 75W-90), where the all-season nature of the liquid is emphasized by the presence of a double digital index.
In the designations of winter (all-season) oils indicated on the packaging for these liquids, the first digit (before the letter W) is the lower temperature at which this oil can be used, and the second digit (after the letter W) is the viscosity index. Thus, the lower the first number, the lower the temperature threshold for operating the oil before it freezes in the cold.
Currently, motorists most often use all-season types of oils. At the same time, the most universal oil for manual transmission is 75W-90. It performs excellently, working in almost all possible conditions with any manual gearbox.
Division of oils according to their performance qualities
This classification was developed by the American Petroleum Institute, whose abbreviation - API (American Petroleum Institute) - gave its name to the quality standard. This standard defines the basic performance properties of lubricants.
It is about the ability of each specific oil to function as an effective detergent, resist the possibility of scuffing on the surfaces of rubbing parts, suppress the appearance of foam, as well as other properties that improve and facilitate the operation of a manual transmission.
Changing the oil in a manual transmission requires correct sequence performing this work.
According to standard API quality, all oils for manual transmissions are designated by the letters GL followed by digital code from 1 to 5 inclusive. These numbers indicate the following properties:
- GL-1 is a mineral-based oil with no additives;
- GL-2 – box oil, which contains high-fat products;
- GL-3 – oil containing anti-scuff additives;
- GL-4 – complex transmission fluid, containing anti-wear, extreme pressure and other additives;
- GL-5 is a higher quality analogue of the anti-wear and extreme pressure oil GL-4.
It should be noted here: the higher the digital index in the lubricant marking, the more actively the indicated operational capabilities of a particular oil are manifested. Typically, working fluids in the range from GL-1 to GL-3 inclusive are used in manual transmissions of used cars, while oils of other brands are used in the transmissions of passenger cars. different types. Moreover, GL-4 should be poured only into cars with front-wheel drive; for manual transmissions of rear-wheel drive cars, GL-5 is used.
Some general rules for changing gearbox oils
For correct replacement oils, you must study the relevant instructions of the car manufacturer. But in any case, if there is a problem with the gearbox, preliminary diagnostics at a service station is necessary.
If there are no visible problems, then you should be guided by the mileage of the car. In particular, changing the oil in a manual transmission becomes relevant every 25-30 thousand kilometers.
It can signal that it’s time to change the lubricant. visual inspection. In particular, if the oil has darkened and started to smell burnt, you can safely go to the auto store for fresh oil.
Immediately before replacement old fluid It must be completely drained through the hole at the bottom of the oil pan.
Instead of a conclusion
No matter how many manuals and instructions a car owner reads, it is still better to entrust changing the oil in a manual transmission to a qualified specialist at a service station equipped for this. Indeed, in this matter, the desire to save at any cost can play a very cruel joke on the motorist.
