The well-known phrase about the lifelessness of everything under the moon immediately pops up in the head of the owner of the "GAZelle", as soon as his ear catches an extraneous hum somewhere below when the car is moving. Most often this is observed when driving at a speed of at least 30 km / h.
An experienced driver will immediately establish the cause of the "out-of-band" sound: the rear axle, adjustment of the GAZelle gearbox is required. But the devil is not so terrible as he is painted. Extraneous hum is completely eliminated, and with their own hands.
This is serious
Engage in "freelance" sound should be immediate, since procrastination is like death (gear). Violation of the mode of interaction of the gears will lead to their rapid wear and damage to the gearbox. You should not put off the problem in a long box, you need to immediately begin to eliminate it.
Of course, it’s not a simple matter - adjusting the rear axle gearbox (“GAZelle” is a completely repaired machine, as you know). Therefore, we must be prepared that the first results may be far from expected.
But do not despair in case of unsuccessful adjustment, but you need to read the “Operation and Repair Manual” once again and repeat all over again.
Where to begin
Adjusting the GAZelle gearbox will first of all require you to do a trivial operation - draining the gear oil.
First of all, it is necessary to heat the oil in the gearbox. To do this, you can drive a car or, lifting the rear axle on jacks or a lift, start the car and engage the gear. This is necessary for high-quality drainage of oil from the gearbox.
After draining the oil into some proportionate container, you should immediately inspect it for metal chips. The presence of metal in the oil indicates the wear of the gears of the gearbox and the need to replace them with the subsequent adjustment of the gearbox.
Having convinced of the need for repair of the gearbox, remove it and disassemble. If the parts of the mechanism have shells, chips and other defects, then such parts must be replaced, and the gearbox must be adjusted.
Adjusting the bearing clearance
The adjustment of the GAZelle gearbox is done after the final assembly of the mechanism. Having assembled the gearbox, you can begin to adjust it.
For the convenience of adjustment work, we install the assembled gearbox on the stand and fix the yokes of the bearings with an effort of up to 9 kgf. Then, with a special key (a plate, possibly with a welded centering sleeve and handle), we adjust the thermal clearance in the bearings: we tighten the front yoke nut to the stop, and then release it by 3 mm (the distance is well determined by a special displacement indicator).
Adjustment can be carried out without the use of a movement indicator. In this case, the yoke nut is tightened to the stop, and then released by one slot in it. The nut should rotate freely by hand.
This is quite enough to create a temperature clearance of the bearings.
Gear planetary gear shank adjustment
It is necessary to establish a gap between the planetary gear and the shank. To do this, make a mark on the yoke against the cutout of the yoke nut. We set the indicator of displacement on the "planetarka" and, turning the shank of the gearbox, determine the desired gap. Its value should be 0.15-0.18 mm.
If the gap is large, then do the following:
- we unscrew the yoke nut of the front bearing one notch from the mark made before this;
- tighten the yoke of the rear bearing to one notch;
- check the clearance obtained after adjustment;
If loosening the nuts on one cutout does not result in the desired clearance, adjust the nuts for another cutout. This is done until the required clearance between the shank and the planetary gear is reached. After that, we fix the clamps on the yoke nuts.
Such actions do not violate the differential temperature gap adjustment, which, in turn, will not cause the gearbox to overheat in the future.
We check the quality of adjustment on the stand
A tooth contact spot is a sure way to correctly determine how well the adjustment of the rear axle gearbox has been carried out in any machine (“GAZelle” is no exception).
To do this, the driven gear (its teeth) is painted with bright paint.
Then it is necessary to rotate (repeatedly and in both directions) the drive gear by the flange, braking the driven gear. This operation is done before the paint is removed in the areas of contact of the teeth (the appearance of a contact spot).
The location of the spot will tell you the flaws in the adjustment made earlier.
If it is in the region of the top of the teeth, then you should put the ring of the pinion gear of greater thickness. But if the stain is located at the base of the tooth, then the thickness of this ring should be reduced.
In the case where the stain appeared at the narrow end of the tooth, the distance between the driving and driven gears should be increased. If the spot is observed at the wide end, then this gap must be reduced.
If the spot is in the right place, this means that the adjustment of the rear gearbox has been successfully completed, GAZelle is now ready for practical verification of the quality of the performed adjustment work. We set off on a short trip to make sure there is no "freelance" noise.
Checking the quality of adjustment in motion
After the adjustment of the GAZelle gearbox is completed, you should check its quality already practically, on the go. Do not forget to pour oil prescribed in the “Operation and Repair Manual” into the axle gearbox.
The check is carried out in motion, the speed should be about 60-70 km / h, the duration of the trip is 20-30 minutes. An indicator of the quality of adjustment will be the temperature of the crankcase heating - not more than 95 degrees Celsius.
Take care of the gearbox
In order for the rear axle gearbox to guarantee its useful life, it is necessary to carefully and competently operate it.
First of all, you should not:
- overload the car, especially in hot weather;
- pretend to be Schumacher and make abrupt starts;
- to overcome long climbs in one fell swoop - this will lead to overheating of the gearbox;
- pour any oil into the gear case, and also violate the frequency of its change: in the summer - every 35 thousand km, in the winter - after 40 thousand km.
- Remember to check the liner backlash with every oil change. If it is found, it should be eliminated immediately;
By the way, the adjustment of the steering gear ("GAZelle" means) is carried out by a similar technology.