Talking about repairing gearbox

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Vehicle information: 20 18 Volkswagen Passat, 1.4T turbocharged engine, 7-speed dry dual-clutch gearbox, driving about120,000 kilometers.

Vehicle failure: serious oil leakage in gearbox.

The owner's eldest brother is in the car rental business. He has more than 20 cars, all of which he bought himself. I'm here to do routine maintenance for Passat.

During the maintenance, Pang Ge found that the gearbox leaked oil seriously, and there was oil in the wing beam and rear suspension.

And what I am most afraid of is that there are three screws in the ball cage in the half shaft, which may break down at any time.

According to the owner's description, this car was rented out last June165438+1October and was hit. At that time, more than 30 thousand was repaired. The owner now asks Fat Brother to confirm whether the gearbox leaks oil. If it is the owner, he will go to them.

Fat brother replied: the oil must be gearbox oil. Judging from the location of oil leakage, it should be that the front oil seal of the gearbox leaks oil and needs to be hoisted for inspection.

Results: As a result, things were complicated and the repair shop on the gearbox was dismantled. The owner doesn't know what parts have been replaced. In short, it was dismantled and not assembled together. Finally, the gearbox was repaired by professionals. The owner tossed it back and forth several times, and finally decided to go to Fat Brother Xiu.

Maintenance steps:

Prepare to hoist the gearbox.

The gearbox is small in size and easy to disassemble.

DQ200, 0AM gearbox, this 7-speed dry dual clutch gearbox has a very high failure rate, such as frustration, power interruption, dead flash and so on.

This is the legendary dry dual clutch, which looks a bit like a manual disc and a clutch plate.

Even and odd gear double clutch fork, two forks are sleeved together.

Control computer unit, the oil leaked from the gearbox is gear oil, which has nothing to do with the oil in the control computer, and the oil in the computer is separate.

The transmission oil seal does not seem to be leaking.

Judging from the traces, the oil did leak from here.

Fat brother took a closer look and got a fright. How did the gearbox shell crack? This is in trouble. The gearbox housing is the least likely to be damaged. How can we crack it?

Maintenance plan:

Replacing the gearbox assembly is outrageous and fat brother can't accept it.

Replacing the gearbox shell requires disassembling the gearbox, and the price of the shell is nearly 2000 yuan less, not counting the artificial materials such as gearbox decomposition fee.

Welding with aluminum requires disassembling the gearbox. The safest way is to weld both inside and outside. And no one can guarantee whether it will stand the test after welding.

The master talked with Brother Pang for three days. The master has seen the treasure countless times and changed his plan countless times. It is necessary to save money and ensure quality. In the end, Brother Pang made the final decision. I only earned the cost of lifting the gearbox and the decomposition fee. You can weld the gearbox with me, and you can talk about the money yourself.

Remove the gearbox:

First remove the first shaft plug of the gearbox.

It takes skill to pull out this plug, and it will lean to one side after being punctured.

I was dumbfounded at first sight. The oil in the gearbox feels like ink. It can be seen that the gearbox is short of oil and dry and worn. Fortunately, they are all gears like manual gearboxes. If it was cooled automatically, it would have been cold long ago.

When I was about to remove the circlip, I found something was wrong again. No circlip was found in it. The circlip was welded to death by electric welding.

How to fix this? Brother pang thinks this job is impossible, so don't earn money to get into the gearbox. Let's get a professional to repair the gearbox. As a result, people took pictures. They refused to accept the job for more money.

Hey, the gearbox hasn't been repaired yet. We need to change the plug. This is not an ordinary plug with an oil circuit.

After communicating with the owner, Brother Pang decided to find a place to weld the gearbox from the outside. A * * * contacted three companies, and only one dared to weld and never cooperated, 80 kilometers away.

When I arrived at the place, I found that the other party was a professional aluminum welder, mainly engaged in cart maintenance.

After the gearbox is welded, the other party also has professional suppression detection equipment, which is more perfect than Fat Brother expected.

Go back to the repair shop and prepare to install the double clutch.

Need to use special equipment.

Start loading.

After the gearbox is installed, you need to use a computer to match the gearbox. The channel number is 60 and the data count is 400. When the engine is turned off at 254, the power supply is cut off.

Fat brother's test drive: after matching, the gearbox did not feel frustrated from P gear to D gear, and then it was driven out and tried twice, running 100 km national road, 30 km mountain road and 60 km high speed. The upshift of the dual clutch gearbox is really fast, and the upper and lower gears are basically not felt. Fat brother thinks it's really cool that the dual clutch is working without fault.

Check after commissioning:

No trace of oil leakage was found.

Shovel the engine cover clean, there was too much oil leakage last time.

Fat brother concluded: What caused the cracking of gearbox shell? I don't know now. Probably from the last accident. It may be that the axle shaft screw fell off and the differential was screwed here. The shaft inside the gearbox was short of oil and could not be installed properly. In short, the owner means to observe the use, and if it leaks next time, the shell and the gears inside will be removed and replaced. Brother Pang suggested that the owner change the gearbox oil after 5000 kilometers, because this time it was found that there was a small amount of iron pin after metal wear.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.