In 2012, AvtoVAZ announced the start of production of a new small car, Lada Largus. The model is actually a version of the first generation Dacia Logan MCV for the domestic market. It is considered a joint project between AvtoVAZ and Renault, based on the B0 platform. In 2020, the car underwent a light facelift, as a result of which the radiator grille was updated, and the Lada nameplate was removed from the rear of the car. There were no serious modifications to the car. The basic idea was retained; the Polish car is quite popular and is in high demand among car enthusiasts. The model is equipped with a 1.6-liter gasoline engine. But we’ll tell you further what gearboxes are installed on the Lada Largus.
Manual gearboxes Lada Largus
From the very beginning of production, the car was equipped with a manual transmission-5. The transmission ensures optimal transmission of torque from the engine to the drive wheels. Depending on the engine power and torque, the Lada Largus is equipped with either JH 3 540 manual transmission or a similar JR 5 unit . The first type of manual transmission is designed for a 5-seater station wagon with a K7M engine under the hood. There are several versions of the JR5 mechanics:
- JR5551 – for a car with a 7-seater body and a K7M engine;
- JR5549 – for the version with a 5- and 7-seater body and with a K4M engine;
- JR5517 – for van with K4M and K7M engine.
The operating principle of the above units is almost identical and consists in connecting gears with different numbers of teeth. The main task is to ensure a change in torque in strict proportion to the gear ratio. There are several levels of boost for Lada Largus engines: 84, 87, 102, 105 and 106 horsepower. The different power of the motors is a consequence of the production of several modifications of the same 5-speed manual transmission with a certain number of teeth on the gears and gear ratio.
Five-speed gearbox JH3 143 R109095
Designation:
JH – manufacturer designation (Japan Honda Motors, Japan);
3 – transmission option (five-speed manual gearbox);
R – assembly plant (Pakistan);
109095 – serial number of the car body.
The gearbox is a two-shaft five-speed. The gear wheels of direct drives are helical, the reverse gears are made of straight teeth. All live broadcasts are synchronized. The gear wheels located on the drive shaft are made together with the shaft. Oil is supplied to the sliding bearings of the gear wheels mounted on the driven shaft through the axial and radial holes of the shaft due to centrifugal force during its rotation. The gear ring of the reverse drive is made together with engagement clutch III
and
IV
gears. The front shaft support bearings are roller, the rear are ball.
The location of the gearbox in relation to the car body is transverse.
Rice. 1.3. Five-speed gearbox (type JH):
1
,
2
– gear wheels
1st
gear;
3
,
4
- gear wheels
2nd
gear;
5
,
6
— gear wheels
III
gear;
7
,
8
— gear wheels
4th
gear;
9
,
10
— gear wheels
5th
gear;
11
,
12
– reverse drive gears;
14
,
16
– main gear gears;
13
,
15
– drive and driven shafts, respectively
1.3.2. Four-speed gearbox of a UAZ car (old model)
The gearbox is a four-speed three-shaft. The drive gears of the intermediate shaft of the second and third gears are helical and are in constant engagement. The first and reverse gears have straight teeth. The third and fourth (direct) gears are engaged using a synchronizer 12
.
The second gear is engaged using the first gear gear 16
, which in this case acts as a clutch.
First gear and reverse gear are engaged by direct movement of gears 22
. The constant mesh and first gear gears are made together with the shaft. All gearbox bearings are ball bearings. The sliding bearings of gear wheels are lubricated by splashing oil when the shafts rotate.
Rice. 1.5. Four-speed gearbox of a UAZ car:
1
– crankcase;
2
– constant mesh gear;
3
– intermediate shaft bearing;
4
– nut;
5
– intermediate shaft;
6
– plug;
7
— cover of the front bearing of the input shaft;
8
— clutch release;
9
,
13
– drive and driven shafts;
10
- nut;
11
,
17
– front and rear bearings of the driven shaft;
12
– synchronizer clutch;
14
,
15
,
16
– gear wheels Ш, II and I gears;
18
– retaining ring;
19
— bolt securing the rear bearing of the intermediate shaft;
20
,
21
– bearing and axis of the reverse gear block;
22
– reverse gear block;
23
– spacer sleeve;
24
,
25
– gear wheels of II and III gears;
26
- drain plug
1.3.3. Four-speed gearbox for Nissan Datsun
The gearbox is a four-speed three-shaft. All gears, except gear wheels 9
and
14
reverse, helical.
Synchronizer clutch 7 is used to engage 1st
and
2nd
gears (the gearing of wheels 8 and 13 is the first gear, the gearing of gears 6 and 12 is the second gear).
Synchronizer clutch 4 is used to engage III
and
IV
gears (the gearing of wheels 5 and 11 is third gear, when the clutch moves to the left, the drive and driven shafts are blocked to engage fourth gear). The sliding bearings of gear wheels are lubricated by splashing oil when the shafts rotate.
Rice. 1.6. Four-speed gearbox for Nissan Datsun:
1 – crankcase; 2, 17 – drive and driven shafts; 3, 10 – constant mesh gears; 4, 7 – synchronizer clutch I
,
II
and
III
,
IV
gears;
5, 11 – gear wheels III
gear;
6, 12 – gear wheels 2nd
gear;
8, 13 – gear wheels 1st
gear; 9, 14 — reverse gears; 15 – intermediate shaft – gear; 16 – body
Work order
Design of 5-speed manual Lada Largus
Structurally, both manual transmissions on the Lada Largus are similar. They are based on a two-shaft design with synchronizers on all forward gears. This arrangement assumes the presence of two parallel shafts - driving and driven. When the vehicle is moving and the gear is changed from the input shaft gear, torque is transmitted to a specific gear on the driven shaft. This is the work of ordinary and simple mechanics, so the Lada Largus manual transmission does not have any special features. But there are still some differences JH 3 and JR 5 .
JH3 gearbox:
- the gears are switched on and off thanks to a clutch moving along a guide sleeve with a bearing;
- the gearbox is controlled by rigid traction;
- other gear ratios (1st gear – 3.72, 2nd gear – 2.04, 3rd gear – 1.39, 4th gear – 1.02, 5th gear – 0.79).
JR5 gearbox:
- The gearbox clutch is engaged and disengaged using a hydraulic slave cylinder;
- the gearbox is controlled by two flexible cables;
- other gear ratios (1st gear – 3.73, 2nd gear – 2.05, 3rd gear – 1.32, 4th gear – 0.97, 5th gear – 0.82).
The main advantage of the car's 5-speed manual transmission is its compactness. The housing of the unit is made of aluminum, inside of which there are shafts with a set of working gears. In order to ensure the best performance of the shafts, they were equipped with synchronization rings. The design also includes: a crankcase, a speed sensor, a control lever, a gear shift mechanism and other parts that are an integral part of a traditional manual transmission.
Description of the design of the JR5 gearbox
JR5 gearbox
1 – input shaft; 2 – right wheel drive oil seal; 3 – clutch housing; 4 – gearbox housing; 5 – back cover; 6 – breather fitting; 7 – eye-bracket; 8 – gear shift lever; 9 – gear selection lever; 10 – speed sensor or plug; 11 – bracket for fastening transmission control cables; 12 – left wheel drive oil seal; 13 – reverse light switch; 14 – oil filler plug; 15 – tube for supplying fluid to the working cylinder of the hydraulic clutch release; 16 – clutch release bearing.
The gearbox is two-shaft, with five forward gears and one reverse gear, with synchronizers in all forward gears. It is structurally combined with the differential and main gear.
The gearbox marking is located on the bottom of the crankcase.
The transmission housing consists of three parts: the clutch housing, the transmission housing and the rear transmission housing cover.
The clutch release drive is hydraulic. The clutch release bearing and the slave cylinder are made as one unit, which is attached to the clutch housing with two bolts.
The clutch housing and gearbox housing are cast from aluminum alloy, and the rear cover is stamped steel. The clutch housing is attached to the gearbox housing with screws. During assembly, a gasoline-oil-resistant gasket sealant is applied between the crankcases. The back cover is attached to the box housing with three bolts.
The input shaft is made as a block of drive gears, which are in constant mesh with the driven gears of all forward gears. The gears of all forward gears are helical, and the reverse gears are spur gears. Gears of 1–4 gears are made integral with the input shaft, the fifth gear gear rotates freely on the shaft. The fifth gear synchronizer is installed at the rear end of the input shaft. The secondary shaft is hollow; oil is supplied through it to the driven gears. The shaft contains driven gears and synchronizers for 1–2 and 3–4 gears.
The fifth gear gear is mounted on the shaft with splines. On the clutch housing side the secondary shaft bearing is roller, and on the cover side it is ball bearing. An oil sump is located under the roller bearing of the secondary shaft, directing the flow of oil into the shaft. All parts installed on the secondary shaft are pulled together into a package with a bolt screwed into the end of the shaft from the cover side.
The driven gear of the main gear is installed on the differential box. The differential box contains two satellites and two side gears. The satellites rotate on an axis fixed in the differential box.
The side gears are connected to the splined shanks of the housings of the internal hinges of the front wheel drives.
Gearbox control mechanism
1 – gear selection cable; 2 – gear shift cable; 3 – control mechanism; 4 – gear shift lever; 5 – gear shift lever cover; 6 – gear shift lever handle.
The gearbox control drive consists of a control mechanism installed in the vehicle interior on the floor tunnel, and a gear shift mechanism located in the gearbox housing. The mechanisms are connected by two cables: selecting and engaging gears.
The transmission control mechanism is secured to the floor tunnel with four bolts.
When selecting one gear or another, the gear selector cable moves the gear selector lever, which, in turn, installs the gear selector in the groove of the corresponding gear shift fork. Once a gear has been selected, the shift cable rotates the lever to engage the desired gear. The shift cable and gear selection cable are not interchangeable.
The breather fitting is a plastic sleeve inserted into the crankcase hole
The gearbox communicates with the atmosphere through a breather located in its upper part.
A hose is attached to the breather fitting, at the upper end of which a plastic tip is attached
During maintenance, the tip on the hose should be turned several times to clean it. The gearbox is filled at the factory with gear oil designed to last its entire service life. The oil level in the gearbox should be at the level of the lower edge of the oil filler hole, closed with a plastic plug.
The article is missing:
- High-quality photos of repairs
Source: https://wiki.zr.ru/139-2_Largus
The article is missing:
- Partial list of parts and consumables
JH3 reliability
The JH3 gearbox is considered a reliable unit, therefore it is still relevant in the automotive market. Car owners prefer cars with a structurally simple gearbox, partly because of its accessible and cheap maintenance. The disadvantages of manual transmission boil down to the lack of a high level of driving comfort. The gear shift does not always occur clearly and quickly; sometimes there are jolts and jerking of the vehicle. Structurally, the unit has been fully studied, so even in the event of a serious breakdown, its overhaul will not be difficult. Usually the lever for switching from one speed to another becomes loose ahead of time, which leads to unclear switching.
Often, owners of Lada Largus with JH3 note the noisy operation of the manual transmission and a crunching sound when engaging reverse mode. Early wear of the synchronizers cannot be ruled out. If we close our eyes to some shortcomings, we will get decent mechanics that can go 200-300 thousand km without a single repair. There are known examples of cars that have covered about 500 thousand km on JH3 without a single repair. Much depends on your driving style and quality of service. The oil change must be carried out in accordance with the maintenance regulations.
JR5 reliability
It’s difficult to praise the mechanical JR5 in any way, but there’s nothing particularly to reproach either. The unit itself is structurally simple, often hums, and the clarity of gear shifting leaves much to be desired. Over time, it requires overhaul or, in severe cases, replacement due to the destruction of key mechanisms. Often, car owners have to disassemble the box because the 5th speed refuses to turn off. The reason, as a rule, is the wear of the rear gear retaining spring. It can burst at any moment, and one of its fragments usually falls under the 5th speed fork. As a result, while driving, the driver realizes that the 5th speed does not turn off.
A roller bearing with a plastic cage on the secondary shaft is another weak point of the JR5 mechanics. The separator often falls apart even at short mileage, which leads to balls clumping together. At a minimum, the manual transmission starts to hum, but there have been cases when balls got caught between the gears. The deficiency was eliminated after the JR5 modernization. Many problems can be avoided if you follow the manual transmission maintenance regulations and use original oil. It is advisable to change the working material of the box every 50-60 thousand kilometers. Tranself TRJ 75 W -80 is suitable for replacement . After passing 10-15 thousand km, it is necessary to take control measurements of the fluid. In general, the box is old, moderately reliable, but not perfect. With the right approach it will last a long time and can be repaired without problems.
What is the result?
Mechanical boxes for Lada Largus are moderately reliable, low maintenance, and easy to repair. There shouldn’t be any problems finding a qualified automotive specialist capable of rebuilding a JH3 or JR5, even in a small city. You should not pay attention to the manufacturer’s statement regarding the maintenance-free manual transmission. Experts recommend changing the oil at least every 80 thousand km, ideally after 60 thousand km. If even minor malfunctions occur (knocking, crackling noises made by the gearbox, gears not engaging), you should immediately go to a service station for a comprehensive diagnosis. Timely minor repairs will prevent the development of a serious breakdown and will save the car owner’s time, nerves and money.
Lada Largus
Lada Largus
Manual transmission JH3
Manual transmission JR5
Tranself TRJ 75W-80 gear oil
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Oil change intervals
First, let's look at how often the lubricant in Logan transmissions needs to be changed. In the official regulations, the Renault Logan manufacturer does not indicate the frequency of replacement of lubricating fluid in cars of 2006, 2014 and other years of production. The lubricant is poured into the transmission for the entire service life of the vehicle.
When is a lubricant change still required:
- if the liquid has lost its properties and cannot properly lubricate parts;
- when vibrations occur in the operation of the transmission;
- when knocking out the gear shift lever;
- if there is a burning smell coming from the box.
Unlike an automatic transmission, in which ATF plays the role of a working fluid, in a manual transmission the oil serves to remove heat and reduce wear on rubbing pairs. But even in this mode of operation, irreversible chemical and physical processes occur; the oil is filled with a suspension of wear products from rubbing metal surfaces.
We recommend making the first replacement at 60 thousand km. During the first tens of thousands of kilometers of a vehicle's run, parts are worn in inside the gearbox. After the break-in period, the amount of wear products in the oil decreases, so the interval between subsequent replacements can be increased to 80-100 thousand km.
We recommend making the first replacement at 60 thousand km. During the first tens of thousands of kilometers of a vehicle's run, parts are worn in inside the gearbox.
After the break-in period, the amount of wear products in the oil decreases, so the interval between subsequent replacements can be increased to 80-100 thousand km.
