Gearbox JH3, JR5, 21809 — design description (Largus 1)

Depending on the configuration, the car is equipped with five-speed gearboxes Renault JH3 and JR5, as well as VAZ-21809 (since 2018), made according to a two-shaft design with synchronizers for all forward gears and combined with a differential and final drive. At the factory, the gearbox is filled with transmission fluid that is designed to last the entire service life of the vehicle. Therefore, there is no need to change the oil in the gearbox according to the maintenance schedule.

Gearbox JH3

A car engine, like all internal combustion engines, develops power and torque in a relatively narrow range of revolutions. As the engine speed decreases, the power decreases.



The power transmission allows the number of revolutions of the drive axle to be reduced in relation to the number of revolutions of the engine crankshaft, increasing the traction force. The higher the traction force, the lower the travel speed.

When driving a car, there is a need to apply different driving speeds and different traction forces. For example, when driving on deep sand, the speed is insignificant, and to overcome the resistance of the road, a fairly large traction force is required. A large traction force is also required when starting the car from a standstill and when overcoming steep climbs. On the contrary, when driving on a hard-surface road, little traction is required, but the driving speed can be high.

To increase or decrease the traction force on the drive axle with a constant torque value on the engine shaft, a gearbox is used in the vehicle's power transmission.

Since the engines of different car models have different power, then, of course, the gear ratios of individual gears, and, consequently, the number of teeth of gear wheels are different. However, the principle of operation of gearboxes is the same, and the operations of disassembly, assembly and repair are generally similar.

The purpose of the gearbox is to ensure further transformation of torque in magnitude and direction in accordance with the load on the vehicle, as well as to create the ability for the engine to operate at idle speed.

The basic principle of operation of the gearbox is the same everywhere, the essence of which lies in the paired connection of gears that have a different number of teeth. In this case, the torque transmitted by the gears changes proportionally to the gear ratio, i.e. the ratio of the number of teeth on the driven gear to the number of teeth on the driving gear.



The gearbox is, in principle, a very simple device.





The rod is attached at one end to the bushing of the gearbox control mechanism, and at the other end to the shift mechanism installed on the gearbox.

Gearbox JR5

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

Gearbox VAZ-21809

Redesigned VAZ gearbox with cable shift drive. It has been installed on Lada Largus instead of the JR5 gearbox since 2018, paired with a 16-valve VAZ-21129 engine. Together with foreign engineers, a number of improvements were made to the gearbox in order to reduce noise and vibration, including the gear tooth profile was changed. The clarity and balance of gear shifting has been improved.

Gear ratio tables for LADA Largus gearboxes

Note: gear ratios on cars with AvtoVAZ engines differ from those shown.

	5 seats with K7M	7 seats with K7M	5 and 7 seats with K4M	Van with K7M and K4M
Transmission	JH3 540	JR5 551	JR5 549	JR5 517
1st gear	3,727	3,727	3,727	3,727
2nd gear	2,048	2,048	2,048	2,048
Zya transmission	1,393	1,321	1,393	1,321
4th gear	1,029	0,971	1,097	0,971
baya transmission	0,82	0,795	0,892	0,738
Reverse gear	3,545	3,545	3,545	3,545
The main couple	4,214	4,5	4,214	4,928

Gear ratios of the VAZ-21809 gearbox

l	3,636
II	1,952
III	1,357
IV	0,941
V	0,784
Reverse	3,500
Main gear	3,944

Factory designations and parameters of the fifth gear

Gear ratio	Primary shaft gear		Secondary shaft gear
	Number of teeth	Part designation	Number of teeth	Part designation
0,892	37	8200611295	33	8200608035
0,820	39	8200611299	32	8200607980
0,795	39	8200611297	31	8200607978
0,756	41	8200611301	31	8200607981
0,738	42	8200611303	31	8200607983

Weight of gearboxes (gearbox weight in kilograms)

• JH3 - 33.0 kg
• JR5 - 34.0 kg
• 21809 - 31.8 kg

Checkpoint identification

Determination of the installed gearbox by configuration and engine (only for engines. Renault).

Body and engine	Station wagon 5 seats with K7M	Station wagon 7 seats with K7M	Station wagon 5 and 7 seats with K4M	Van with K7M and K4M
Installed Checkpoint	JH3 540	JR5 551	JR5 549	JR5 517

The ratio of engines and gearboxes is indicated in more detail here.

Note: For precise identification of the installed gearbox, see its marking (see below).

The material was taken from a website ladaman.ru

Plate 1, Figure 2-1, stamped on the gearbox housing using impact method, provides information about the gearbox, Figure 2-2.







Markings on gearboxes are located at the bottom, on the crankcase.

The gearbox code is on a sticker located on the rear, black cover of the gearbox (on the left in the direction of travel). Although it is difficult to see it on the car, it is possible:

Differences in the designation of the CP

Production of AVTOVAZ

External supply