Rear axle gearbox gazelle DIY repair

GAZelle rear axle gearbox repair requires precise adjustments and it is desirable to carry it out in specialized services. If you are confident in your abilities, then especially for you we provide step-by-step instructions for adjusting the rear axle gearbox on GAZelle cars. Before starting repairs, read about the device of the gazelle rear axle reducer.

After removing the gearbox, we proceed to disassemble it, having previously clamped it in a vice. We unscrew the bolts that secure the locking plates and remove them.

It is worth marking the bearing caps so that in the future they do not confuse the places where they need to be installed. Unscrew the bolts with a 14 wrench, remove the covers.

We also remove the adjusting nuts and the outer races of the roller bearings.

Inspect bearings for suitability, label each outer race.

Check the backlash in the semi-axle gears, it should not exceed 0.5mm, otherwise the differential box will need to be replaced. Remove the bearing and unscrew the planetary gear.

We knock out the axis of the satellites and take it out.

We take out the drive shaft with the gear from the gearbox housing and knock out the inner ring of the roller bearing with a soft metal drift. We replace the adjusting sleeve with a new one.

Remove the adjusting ring.

Using a punch, it is necessary to knock out the outer rings of the bearings.

We wash over all the details, inspect. Parts must be replaced if they are chipped, cracked, or have shells. We polish the seizures with sandpaper.

Next, we start assembling. If all the parts are the same, then we only change the spacer sleeve and the oil seal. If something was changed on the main pair, then we also change the spacer washer, we select it according to the size indicated on the new shaft. We install a new ring and press in the inner bearing race.

We install a new spacer sleeve on the shaft and put it in the gearbox housing. We put a new oil seal. We put on the flange, tighten it with a new nut.

We collect the differential, put it in place. If backlash was found in the side gears, then thickened washers will be needed. We tighten the covers.

We make a special key for adjustment.

We start adjusting. We wrap the nut from the side of the driven gear until the gap disappears. We measure it with a caliper.

After tightening the second nut, tighten another 1-2 teeth. With the first nut, the gap is adjusted to 0.08-0.13 mm. We tighten both nuts until the distance increases to 0.2mm.

We turn the gear by hand and check the backlash - it should be the same in different positions. Install the locking plates and bolt them. The differential must be replaced if the backlash is not the same.

There comes a time when there are extraneous noises, howling, rustling, grinding in the main gear of a Gazelle car, the gearbox heats up. This is a reason for an urgent inspection of the liner for the presence of backlash and oil, for the presence of metal shavings, metal debris in it. Perhaps repairs and adjustments are needed, because the first signs of breakdown are obvious.

1. Advice. Before getting started, weigh your knowledge and capabilities. Maybe it's better to contact a car service! If you are confident in yourself, start.
2. For convenience and safety, install the gearbox on a stand, or clamp it firmly in a vice. Believe me, the repair of such a unit requires a rigid attachment and nothing will work on the table or floor.
3. The work begins with the installation of marks on the bearing caps and the crankcase. They are needed so that during assembly the parts fit strictly into place.

1. Unscrew the bolts with a 12 key and remove the yoke stopper.Using the "17" head, unscrew the four bolts of the bearing caps. They come off easily if you lightly tap them with a hammer.
2. With a special key - it can be made from a steel strip and a piece of round timber - or with a large screwdriver, unscrew and remove the yoke. The differential is free, dismantle it.

1. Now you need to remove the driven gear. To do this, unscrew 10 bolts with a "17" head, knock it down with a soft metal hammer or through a drift.
2. Before disassembling the differential box, put marks on both cups and unscrew 8 bolts with the head "13" separate them.
3. Remove the first half-axle gear.
4. Carefully knock out the crosspiece with a hammer and disassemble it, removing washers and satellites from their axles.
5. Remove the second gear.
6. To make it convenient to remove the flange, lock it, unscrew the nut and unscrew it with the "24." The flange can now be easily removed.
7. Pull the drive gear out of the crankcase and remove the spacer sleeve, the adjusting ring, and using a puller, the inner and support bearings, the adjusting washer, and knock out the old oil seal from the body and remove the outer bearing.
8. Using a drift, remove the bearing races.

Wash all parts with kerosene, carefully inspect and reject. If necessary, replace them with new or used ones, but suitable for service. Remember that in a gear pair - the main gear - the gears do not change one by one. That's why they are a couple.

Assembling the gearbox is a complex and responsible process due to the presence of the necessary adjustments, for which special devices are needed. There is no point in describing them, since they are intended only for gearbox adjustments.

The time of using the assembled gearbox, which means its performance, depends on the quality of these works and the correctness.

The rear axle gearbox is one of the main components of the car, the basis of the differential. Its task is to distribute and change the torque that is transmitted from the engine and gearbox to the drive wheels. Structurally, this unit is very complex, so one day you may need to configure and adjust it. But more about everything.

The differential can have a different location (it all depends on the drive of the vehicle). For example, in four-wheel drive vehicles, the unit can be located in the gearbox or housings of both axles, in cars with front-wheel drive - directly in the rear axle housing.

Differentials, which are the driving force for the drive wheels, are called interwheel differentials. In vehicles with four-wheel drive, center differentials are installed, which are located between the two axles.

It is important to note that the differential is structurally in the form of a reducer. Depending on the type of gear transmission, the assembly can be worm, cylindrical and bevel. Each of them uses its own gear - worm, cylindrical and conical, respectively. The most popular today is the fourth type - hypoid gears. Their advantages include lightness, minimal size and reliability.

As we have already mentioned, the axle gearbox is a very complex unit that requires a special approach to adjustment and tuning. As a rule, such work must be carried out immediately after the repair of the unit or its disassembly. In the course of current operation, there is no need for adjustment work, because all clearances and bearing adjustments are made with perfect accuracy at the factory. If there is a bridge overhead, replacement of some parts or repair, then the adjustments go astray. They need to be restored.

During operation, wear of the teeth in the gearbox is possible - this is a common thing. This will increase the side play in the final drive. It would seem that adjustment can be a lifesaver. But no. Such intervention can only worsen the situation and lead to the appearance of unnecessary noise.Moreover, incorrect operation may result in tooth breakage, which will require the replacement of the entire assembly.

Adjustment of the axle reducer is necessary in the following cases - when there is a strong hum during movement and backlash of the drive gear. At the same time, do not delay the work, because the lack of timely adjustment can lead to more serious destruction of the unit and its complete failure.

The Gazelle car is a reliable and high-quality transport, which is distinguished by its unpretentiousness and high carrying capacity. But the frequent use of equipment and its operation in extreme conditions (with a heavy load and on bad roads) often leads to problems with the gearbox. As a result, the problems that we mentioned above appear.

In such a situation, you can act in two ways - go to the service station and entrust the gearbox setting to professionals, and the second - do the work yourself. But be honest with yourself. If you have certain knowledge, strength and confidence, then you can carry out the adjustment work yourself and save money. In the absence of experience in such work and a knowledgeable person at hand, it is still better to give the gearbox to professionals in their field.

So, let's look at the features and subtleties of the adjustment:

1. Remove the rear axle gear and clamp it in a vise. Many newbies lay the knot on the table and begin disassembling. This is the wrong approach. First, it will be inconvenient to disassemble the gearbox in this case. Secondly, you will not be able to put all the necessary marks and will lose half of the details.
2. Be sure to mark the bearing caps. During assembly, this will allow correct installation.
3. Take the key on "14", unscrew the bolts and remove the covers.
4. Unscrew the adjusting nuts (not needed yet).

1. Remove the outer race from the roller bearings.
2. Inspect the bearings carefully for damage and reuse.
3. Check the axle gears for backlash. According to the rules, it should be no more than 0.5 mm. If the backlash is too large, then it will be necessary to change the differential box.
4. Dismantle the bearing and unscrew the planetary gear.
5. Knock out and take out the axis of the satellites.

1. Pull out the drive shaft (located in the gear housing).
2. Using a special soft metal spacer, try to knock out the ring located inside the roller bearing.
3. Install a new adjusting sleeve.
4. Pull out the adjusting ring.
5. Knock out the bearing rings (outside). Use a spacer again to avoid damaging the metal.
6. Wash all parts of the gearbox and carefully inspect them for damage. If any of the elements have cracks or chips, then it is better to replace them. If common seizures appear, they can be removed with sandpaper.
7. Next, proceed to disassemble the assembly. If there are no additional defects, replace only the oil seal and the bushing. If any replacement was made in the main pair, it is better to install a new spacer washer.
8. Install a new ring and press in the inner part of the bearing race.
9. Place the spacer sleeve on the axle (we have replaced this unit).
10. Install the shaft into the gear case.
11. Install a new oil seal.
12. Tighten the flange and secure with a nut.
13. Assemble the differential and return it to place. If there is any play in the side gears, be sure to install thicker washers.
14. Replace the covers.
15. Using a special adjustment wrench, tighten the nut (the one located on the side of the driven gear) until the gap disappears.
16. Measure with a barbell.

1. After pulling the second nut, tighten it a few more teeth. After that, using the first nut, adjust the gap - it should be 0.08-0.13 mm.
2. Tighten both nuts until the distance increases to 0.2 mm.
3. Turn the gear and make sure that the backlash is approximately the same in all positions.
4. Replace the retaining plates and screw in the bolts.
5. If the play is different, replace the differential.

Of course, adjusting the bridge gearbox on a Gazelle is a very laborious process. When you complete all the necessary actions, you will spend about 3-4 hours, but you will save several thousand rubles. Good luck.

Strange sounds are heard from the axle shaft, the repair of the Gazelle rear axle gearbox is inexorably approaching and this is a confirmed fact. This topic will be relevant specifically for drivers who own cars of the "C" class, because for them a more familiar concept is the differential. It all starts with the fact that the sound is not too loud, but if you do not figure it out in time, it will become stronger with each kilometer traveled. As a result, the axle shaft or even the entire axle assembly can be completely broken. It already turns out that not all drivers know where in the car what mechanisms are located, and therefore, not everyone has the opportunity to repair the car himself, although everything is quite simple in reality. It will take at most an hour of free time. Plus, you don't even need to have any special experience. One has only to follow the advice that will be given in the article.

The repair of the gearbox of the rear axle of the Gazelle can be started only after the person is one hundred percent sure that it is in this particular unit. Without doing this, you run the risk of seriously screwing it up, leading to additional costs.

Actually, the sequence of actions is as follows:

• Before entering a lift or a pit, let the machine run a little. Enough if she covers a short distance, about 5-6 kilometers. The speed should be different. This is necessary to warm up the fluid in the axle shafts, in order to then completely drain it. If it is thick, it will not be possible to do it as efficiently as necessary.
• Shoes are placed under the rear or front wheels to give it stability.
• The plug is unscrewed. In its place, any empty container is immediately substituted, which should be prepared in advance. Its volume should be equal to six liters.
• When draining the oil, take a closer look at the condition in which it is. Probably, it will be possible to consider micro particles of metal in it.

First of all, the machine does not need to be subjected to too high loads. Plus, drivers need to try to drive in first gear as little as possible, and, if possible, switch to second gear as soon as possible, because the first increases gearbox wear. Do not start off abruptly, because this is how the splines are torn off the rod. As for the oil change, it should take place after forty thousand kilometers.

Those who have read the article can now consider themselves a master who can easily repair the gearbox of the rear axle of the Gazelle. It should be remembered that the Gazelle is not the car in which you need to start abruptly from a place!

We assemble the main gear in the reverse sequence to disassembly, lubricating the bearings and gears with transmission oil.
Having installed the drive gear in the gearbox housing, ...

… With a torque wrench, tighten the flange nut to a torque of 16–20 kgf.m, while the gear must be turned to properly install the rollers in the bearings.

We install an indicator with a graduation value of not more than 0.01 mm on a tripod, resting its leg against the end of the flange ...

... and moving the shaft behind the flange, we measure the axial play of the drive gear.

To eliminate the backlash, remove the spacer ring installed on the pinion shaft (see Dismantling the rear axle) and measure its thickness with a micrometer.
We select and install a new spacer ring. It should be thinner than the removed backlash and an additional 0.05 mm thinner if the pinion bearings are new, or 0.01 mm if the bearings are the same.
In the absence of axial play of the drive gear, we check the torque of resistance to the rotation of the shaft with a special torque wrench with a division value of up to 0.5 kgfm. With correct adjustment, the moment of resistance should be 15–20 kgf.cm for new bearings or 7–10 kgf.cm - if the bearings are left as they were.
With sufficient accuracy, the moment of resistance can be measured with a household steelyard, ...

... by hooking it into the hole in the flange.

In this case, the required values ​​will be less - 3.8–5 kgf and 1.8–2.5 kgf, respectively. If the moment of resistance is greater, we change the spacer ring to another one, thicker by 0.01–0.02 mm, if less, then we select a ring of smaller thickness.
The bolts for fastening parts of the differential box and bolts for fastening the driven gear, as well as their threaded holes, are degreased and covered with an anaerobic sealant before assembly. We pay special attention to the cleanliness of the end surfaces of the gears and the gearbox of the satellites, the slightest dirt or nicks are unacceptable.

When installing the driven gear on the satellite box, we center it using long M10 × 1 bolts (you can use bolts from old connecting rods).

When installing the driven gear on the satellite box, we center it using long M10 × 1 bolts (you can use bolts from old connecting rods).
Using the adjusting nuts, we tighten the differential bearings with a slight preload, while turning the gear in one direction or the other so that the bearing rollers take the correct position.

To measure the lateral clearance in the meshing of the main gears on the rear axle housing, we fix the indicator by bringing its probe to the top of the tooth on the outside of the driven gear.

The gap should be 0.15–0.20 mm. The measurements should be repeated on at least six teeth in opposite areas of the rim.
To reduce the gap (with a screwdriver or a thin steel rod), loosen the adjusting nut on the side opposite to the driven gear, and tighten the other.
Unscrew one nut and tighten the other by the same amount, focusing on the grooves of the adjusting nuts. In this case, each unscrewing of the adjusting nut must be completed by slightly tightening it. For example, to loosen a nut five notches, unscrew it six and then tighten one notch.
This will ensure that the outer ring of the bearing is in constant contact with the nut, thereby ensuring that it is secured during operation.
To increase the gap, repeat the entire procedure in reverse order.
After adjusting the lateral clearance in the engagement, we check the axial play in the differential bearings, for which:

… We fix the indicator on the tripod, resting its probe against the end of the driven gear. Swinging the gear in the axial direction, we measure the backlash in the differential bearings.

Using the adjusting nut located on the opposite side of the driven gear, we set the axial play 0.035–0.055.
Further, tightening the nut, set the bearing preload: 0.1 - when the bearings run less than 10 thousand km; 0.05 - with a run of more than 10 thousand km. Turning the nut one groove corresponds to "compression" of the bearing by 0.03 mm. After adjusting, tighten the bearing cap bolts and install the lock plates (see Rear Axle Disassembly) and re-check the side clearance.

ATTENTION
Before the final tightening of the cover bolts, turn them out one by one and apply an anaerobic sealant to the threaded part.

Adjusting the final drive by the contact patch of the teeth is an effective way to adjust the gear engagement. It also allows you to check the quality of adjustments made in other ways.

Apply paint, preferably a bright one, to the teeth of the driven gear.

We rotate the drive gear flange several times in both directions, at the same time slowing down the driven gear until the paint abrades at the contact points of the teeth.
We examine the contact spots on the teeth of the driven gear from the convex and concave sides.
If the contact patch is located at the top of the teeth, it is necessary to increase the thickness of the adjusting ring at the pinion gear, and if at the base, reduce it.
If the contact patch is displaced to the center of the gear, it is necessary to increase the gap between the driven and driving gears, and if outward, to reduce.
After adjustment, we install the gearbox in the rear axle, while applying a thin layer of oil-resistant sealant to the mounting bolts and flange.
Having assembled the rear axle and filled it with oil (see Changing the oil in the gearbox), we test the gearbox on the fly. To do this, we make a trip at a speed of 60–70 km / h for 20–30 minutes. Heating of the crankcase throat should not exceed 95 ° (water droplets should not boil).
Otherwise, it is necessary to reduce the preload of the pinion bearings.

Contact patch in the final drive gears

A - forward sides;
B - reverse sides;

1 - the correct location of the contact patch;

2 - the contact patch is located at the top of the tooth - to correct, move the drive gear to the driven one;

3 - the contact patch is located at the base of the tooth - to correct, move the drive gear away from the driven one;

4 - the contact patch is located at the narrow end of the tooth - to correct it, move the driven gear away from the driving gear;

5 - the contact patch is at the wide end of the tooth - to correct it, move the driven gear to the driving gear.

The gazelle is very popular today in the segment of small commercial vehicles due to its low cost and good operational properties. The gearbox of the rear axle of the Gazelle, like most other units, is reliable in conditions of intensive use of the car on our roads.

Rear axle design Gazelle

The welded rigid beam is made of stamped steel sheets and consists of the final drive housing and half-axle casings pressed into it ("banjo" type). Additionally, spring pads, shock absorber brackets, a gearbox mount, a rear cover, trunnions with flanges for mounting hubs, a rack for a brake regulator are welded. On top of the cover of the left axle shaft there is a breather for ventilation and protection against pressure build-up.

The main gear and differential are removable, bolted in the crankcase. To ensure smooth running, low noise level, high load capacity with small dimensions, a hypoid transmission with a downward-shifted pinion gear axis is used. Gear ratio for modifications with ZMZ engines 5.125 and 4.556 for the UMP engine. It is possible to equip some cars with an old-style non-separable rear axle. The main gears are matched by a pair according to the contact patch and noise, therefore, they must be replaced as an assembly.

The node is reliable, but in order to postpone the repair, it is periodically necessary:

• check the oil level;
• clean the breather from dirt;
• tighten the nuts of the drive gear flange and the axle shafts;
• control the adjustment of the differential bearings and wheel hubs.

For lubrication, gear oil of class GL-5 is used, the total volume is 3 liters (2.2 in fixed version). Replacement is carried out according to the manufacturer's recommendations after 48,000 km of run, but during intensive operation with high load it is better to change the oil after 30-35 thousand. It is necessary to drain after the trip, hot oil will flow out faster and more completely. If there are metal particles on the magnetic drain plug, you can flush the crankcase for ten minutes with a mixture of oil and diesel fuel or kerosene. After filling, lift the left and right wheels alternately with a jack for 10 minutes to lubricate their bearings and add gear oil.

Repair and replacement of the Gazelle gearbox

The need to carry out repairs is indicated by extraneous noise from the rear axle. More often it is a humming, less often howling, the sound intensity can be from subtle to causing discomfort.Only a slight hum in some modes is conditionally permissible, avoiding them, you can still operate the Gazelle gearbox.

Inspection and repairs are carried out on the removed gearbox. For dismantling, the oil is drained, the propeller shaft and rear axle shafts are disconnected, the mounting bolts are unscrewed. The repair is quite complicated, it involves the use of pullers, hot pressing of bearings, the use of a torque wrench, and a number of specific precise adjustments. A specialized car service with experience will better cope with these tasks; you can independently replace the gearbox assembly or the entire rear axle.

In addition to the standard two variants of the gearbox for the Gazelle, there are modifications with a self-locking differential. The maximum blocking factor is 70–80% (complete blocking is not possible), the price is 2-3 times higher, the use of a special gear oil is required. It is possible to install a gearbox from Sobol, the dynamics of the car will improve, but the resource will be less. A unit with electronic blocking control is quite rare; its price is 4–5 times higher than that of a standard gearbox.

To prolong the life of the rear axle gearbox, follow these guidelines whenever possible:

• do not exceed the maximum carrying capacity of the vehicle, especially at high temperatures;
• use first gear only for pulling away, do it smoothly;
• try not to slip;
• carry out maintenance on time using quality oil.

We examined the disassembly of the axle gearbox in the article - How to disassemble the rear axle of a Gazelle car

In this article, we will consider how to properly assemble and adjust the gearbox of the rear axle of a Gazelle car.

We assemble the main gear in the reverse sequence to disassembly, lubricating the bearings and gears with transmission oil.

Having installed the drive gear in the gearbox housing, tighten the flange nut with a torque of 16–20 kgfm with a torque wrench, while the gear must be turned to correctly install the rollers in the bearings.

We install an indicator with a graduation value of no more than 0.01 mm on a tripod, resting its leg against the end of the flange and moving the shaft behind the flange, measure the axial play of the drive gear

To eliminate the backlash, take out the spacer ring installed on the gear shaft (see - How to disassemble the rear axle of a Gazelle car) and measure its thickness with a micrometer.

We select and install a new spacer ring.

It should be thinner than the removed backlash and an additional 0.05 mm thinner if the pinion bearings are new, or 0.01 mm if the bearings are the same.

In the absence of axial play of the drive gear, we check the moment of resistance to the rotation of the shaft with a special torque wrench with a division value of up to 0.5 kgf.m.

With correct adjustment, the moment of resistance should be 15–20 kgssm for new bearings or 7–10 kgssm - if the bearings are left as they were.

With sufficient accuracy, the moment of resistance can be measured with a household steelyard by hooking its hook over the hole in the flange.

In this case, the required values ​​will be less - 3.8–5 kgf and 1.8–2.5 kgf, respectively.

If the moment of resistance is greater, we change the spacer ring to another one, thicker by 0.01–0.02 mm, if it is less, we accordingly select a ring of smaller thickness.

The bolts of fastening parts of the differential box and the bolts of the driven gear, as well as their threaded holes, are degreased and covered with an anaerobic sealant before assembly.

We pay special attention to the cleanliness of the end surfaces of the gears and the gearbox of the satellites, the slightest dirt or nicks are unacceptable.

The rear axle reducer consists of several units, mainly the main gear and differential. The final drive is a mechanism by which the gear ratio of the vehicle's transmission is increased.What it is, what it affects and how the maintenance of the reduced gearbox is carried out, we will consider in this article.

Let's take a closer look at the gearbox device, which consists of two parts that we have already mentioned. The main gears are classified into single and double, which have one and two gear pairs to transmit engine torque to the wheels, respectively. Double main gears are central (simple design, greater gear ratio, but a large load on the system elements) and spaced (more complex in design, but more efficient, more compact, allows the car to have a higher ground clearance). Single main gears are:

• cylindrical (gears in one plane, maximum efficiency, gear ratio 3.5-4.2);
• bevel (gears are perpendicular to each other, which makes the design take up a lot of space, high efficiency);
• worm (compact, quieter, but low efficiency, heavy to manufacture);
• hypoid (lighter in weight, smaller in size and more reliably transmit engine forces to the bridge, but the efficiency is the most average of the given types of transmissions).

A differential is a mechanism that distributes torque between the drive wheels and the drive axles. The differential assists in slipping and slipping by using different wheel speeds.

The gearbox can fail primarily due to bearings made of bronze, they are located in stockings that are attached to the gearbox itself. If such a bearing breaks down, the stockings are damaged and they begin to bend the shafts. As a result of this bending, the main gear can be skewed. If it is skewed, fractures in the gear teeth or chips can appear on it, and subsequently the gearbox itself can jam, and if the shaft flies out of its place, it threatens to break the gearbox housing.

The cause of the breakdown will also be the oil not poured into the rear axle gearbox in time, to be more precise, its absence or its untimely renewal. The transmission oil is usually changed every 35 thousand kilometers.

It is very easy to notice a gearbox malfunction, when cornering, a sharp deceleration or, on the contrary, acceleration, noise periodically occurs in the area of ​​the rear axle... Do-it-yourself repair of the rear axle gearbox is not so difficult. Let's consider it on the example of a classic VAZ car. The first step is to drain the transmission oil from the rear axle gearbox. While the oil is draining from the housing, we disconnect the propeller shaft.

The next step is to dismantle the axle shafts and for this, first of all, we remove the rear wheels and brake drums. Then we unscrew the bolts securing the gearbox with the bridge. When installing a new gearbox, we use a sealant and do not forget about a cardboard gasket. Fill the gearbox with oil. The gearbox flange must fit snugly in place, as well as the bearings.

The arrangement of the rear axle gearbox itself is not so complicated, and, mainly, a hypoid look is found on rear-wheel drive cars. The whole difficulty lies in the fact that when removing the brake drums, there may be a problem with rust, and in some places the metal can press very hard. But brute masculine power and a few tools will easily solve this problem.