Transmission fluid and filter change at 200K.

nonickatall said:

The former mechanic which made a flush without Filter change, did everything right, because in a transmission only a third of the oil is in the oil pan, the rest is somewhere in the system, for example in the torque converter.

If you want to change the oil, it doesn't actually make sense to remove the oil pan, drain a third of the oil and refill it.

Even if you change the filter of course.

Rather, it makes more sense to flush the transmission by disconnecting the line at the front of the oil cooler.

Let the car run for a short time, until there is no more oil, fill the oil back up and repeat this procedure until clean oil comes out at the front.

Then you connect the line again and restore the correct oil level.

Then the transmission oil is 95% replaced.

And you don't have to be afraid that you damage your transmission, because i a automatic transmission there are no pressure bearings like in an engine, which never should run without oil pressure.

If you stop the engine immediately, when the oil stops to drain, you can not make anything bad to your transmission.

As far as the filter is concerned, you don't have to change the transmission oil filter itself every time.

Because as a rule these are fleece filters that only have the task of stopping larger chunks.

The fine abrasion from the pressure plates is caught on the magnet at the bottom of the oil pan and the abrasion of the friction disks is traveling in the oil, which is why a flushing should be done at some point.

The mechanic who zold you not to change your oil, is an idiot. When an engine, or an automatic transmission, or an differential is old, but still in a good condition, it is always necessary to make proper oil changes and use quality oil.

It even makes sense, to halve the oil change intervals. With an automatic transmission I would normally change the oil every 40,000 km, if the automatic transmission is worth anything to me.

And this is really easy and you can do it yourself, its done in half an our without Filter change, which you not need as i said.

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the 18th letter said:

Theres no way to drain fluid from one of these transmissions? It can only be flushed out?

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strutaeng said:

Yes you can, but what @nonickatall is saying is that a lot fluid still remains in the torque converter. So a drain and refill will essentially only dilute the old fluid with new fluid.

I have the done the fluid replacement by following the same procedure by disconnecting the fluid line at the radiator. I have a clear vinyl tubing I pop on and run into a bucket. I fire up the engine and when the line starts sputtering, I have my 12 year old son kill the engine. Then drop the pan (only small fluid remaining, maybe 1/2 quart), clean the magnet, replace the filter and reinstall.

I pour about 5 qts. of fluid, fire up the engine, then add a few more qts. before shifting through the gears and checking/adding more fluid as necessary.

It's not that bad, just sounds complicated. This is for my trucks with the 4L80e, but 4L60e should be similar.

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the 18th letter said:

Ok. I have to check my mechanic then. He declined to flush the transmission and did a drain a fill with filter. It sounds like he got me for a nice piece of change for a not really useful procedure.

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nonickatall said:

Then you go to this mechanic who is a pro at changing engine oil, probably replaces the spark plugs and if he is an old and adventurous “mechanic” he changed the internal filter once.

But he was very nervous about it.

But he never looked inside the automatic transmission or even understood what was going on inside.

However, he can connect a reading device and if this device informs him of the defective part with the part number, he can replace it if it is “clicked on” or mounted with a maximum of 3 screws.

These mechanics, who are now also widespread in Germany, first learn to say to the customer with conviction:

We have never heard of this problem before.

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the 18th letter said:

It was actually a transmission shop that specializes in transmissions lol. Someone had a good expirience with them and I trusted their experience. When I got there the mechanic drove a 1/2 ton GM truck almost same year as mine. Figured I was good, go figure.

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nonickatall said:

That's the problem, even shops that specialize in something, no longer have a clue what they're doing.

A friend of mine recently went to an air conditioning repair shop to repair the air conditioning on his bus. They filled the system with refrigerant and discovered that there was too much pressure on the low pressure and high pressure sides.

They said the compressor was damaged. So he changed the compressor and the system had the same problem. So you say the expansion valve is the problem and he replaced the expansion valve. Still the same problem.

He asks me...

I'm not a trained air conditioning expert, but I acquired the knowledge at some point, because I want to repair air conditioning systems myself and don't want to have to rely on other people. I mean I understand how an air conditioner works period and if you have too much pressure on both sides then you definitely have too much refrigerant in the system.

So I looked at the capacity table and found that there are two types of compressors for this vehicle that differ in capacity by 100g.

The workshop, which "specializes" in air conditioning service, was unable to do this and filled in 100 g too much, which resulted in the system not running.

Because the mechanic doesn't know what the problem is, they gradually start replacing the system. The error will be hidden somewhere.

With such people, mankind would never have flown to the moon.

We would never invented the stick, the hammer and the wheel with them...

Sometimes I wonder whether it is a special form of humor that such workshops call themselves specialist workshops for air conditioning systems or specialist workshops for automatic transmissions...

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