Four-wheel drive vehicles are equipped with five- or six-speed manual gearboxes.
Five-speed gearbox JR5 and six-speed gearbox TL8.
The JR5 gearbox is installed with the K4M engine. And the TL8 gearbox can be installed with both the K4M engine and the F4R engine.
All gearboxes have a modification for installation on 2WD and 4WD vehicles, which is reflected in the marking on the housing.
The difference of the gearbox for a 4WD vehicle is the presence of a flange for connecting the transfer gearbox and the absence of the right half-shaft gear oil seal (the oil seal is installed on the output shaft of the transfer gearbox).
The TL8 manual gearbox has the same connecting and installation dimensions as the JR5 gearbox, and is in many respects similar to it in design.
The difference is the presence of a sixth gear and the arrangement of the gears and synchronisers on the shafts, as well as a cast rear cover instead of a stamped one.
Gearbox TL8
The gearbox is manual, two-shaft, with six forward gears and one reverse, with synchronisers on all forward gears.
It is structurally combined with the differential and the final drive.
The gearbox body consists of two parts (cast from aluminium alloy): the clutch housing and the gearbox housing.
During assembly, a petrol- and oil-resistant sealant gasket is applied between them.
The driving gears of all forward gears are located on the input shaft and are in constant mesh with the driven gears installed on the output shaft.
The gears of all forward gears are helical, and those of reverse — straight-cut.
The driving gear of the final drive is also located on the output shaft.
The driving gear of the final drive is in constant mesh with the driven gear of the final drive.
The driven gear of the final drive is installed on the differential case and is secured to it by bolts.
Two pinion gears and two half-shaft gears are installed in the differential case.
The pinion gears are installed on an axle secured in the differential case.
The half-shaft gears transmit torque to the front wheel drives.
The differential case rotates on two tapered roller bearings, the inner rings of which are pressed onto the differential case and the outer rings are pressed into the gearbox and clutch housings.
The differential case, by means of a splined connection, transmits rotation to the drive shaft of the transfer gearbox.
The gearbox control drive consists of the control mechanism, installed in the vehicle interior on the floor tunnel, and the gearshift mechanism, located in the gearbox housing.
The mechanisms are connected by two cables: gear selection and gear engagement.
The gearbox control mechanism is secured to the floor tunnel by four bolts.
When selecting a particular gear, the gear selection cable moves the gear selection lever, which, in turn, places the gear selector in the groove of the corresponding engagement fork.
Once the gear has been selected, the engagement cable turns the lever, engaging the required gear.
The gear engagement cable and the gear selection cable are not interchangeable.
The gear selection cable can be adjusted in length.
To change the cable length, it is necessary to compress the spring 2 with the locking bush 3.
After this, we move the toothed retainer 4 (orange in colour) inside the cable terminal, disengaging its teeth from the toothed end of the cable 6.
We move the toothed end of the cable 6 inside the terminal, setting the required cable length, after which we fix the cable end with the toothed retainer 4 and release the locking bush.
The gearbox communicates with the atmosphere through a breather located in its upper part.
During maintenance, the terminal on the hose should be turned several times to clean it.
At the factory, transmission oil designed for the entire service life is poured into the gearbox.
The oil level in the gearbox should be at the level of the lower edge of the oil filler opening, closed by a plastic plug.
The gearbox is a complex assembly, for the repair of which experience and special tools are required.
Therefore, gearbox repairs should be carried out in a specialised technical centre, which has both the necessary equipment and spare parts.
In the event of a serious breakdown or severe wear of the gearbox parts, it is advisable to replace it entirely.
Possible manual gearbox faults and remedies
Cause of fault — Remedy
Vibration, noise in the gearbox:
- Loosening of the mounting or damage to the engine and gearbox suspension mounts — tighten the mounting or replace the mounts;
- Wear or damage to the gears and bearings — repair the gearbox at a service centre;
- Oil of an unsuitable grade has been poured in — pour in quality oil;
- Insufficient oil level — top up the oil to the level.
Oil leakage:
- Destruction, damage to the oil seal or sealing rings — replace the damaged parts.
Difficult gear changing and grating when changing:
- Incomplete clutch disengagement — remove air from the clutch release hydraulic drive;
- Fault of the gearshift drive cables — replace the gearshift drive cables at a service centre;
- Wear of the synchronisers — repair the gearbox, replace the synchronisers.
Spontaneous disengagement of gears:
- Wear of the gearshift forks or breakage of the retainer springs — repair the gearbox, replace the faulty parts;
- Increased clearance of the synchroniser sleeve on the hub — repair the gearbox.
Gear ratios of the manual gearboxes
