How to maintain an automatic transmission

and make it last more than 400,000km

What drain spacing for an automatic transmission?

The automatic transmission oil change must be carried out regularly:
For a GM gearbox on BMW, Ford gearbox (for example on Jaguar S-type): every 60,000Km imperatively. With regular maintenance these boxes are very reliable and can reach 400,000 km. Obviously their lack of maintenance can lead to serious breakdowns from 100,000 km.

For a ZF gearbox: between 80 and 120,000 km depending on use. Without maintenance there can be malfunctions after 100,000km.

For DSG and CVT gearboxes: every 60,000 km absolutely.

How much oil to use when changing automatic transmission?

The quantity of oil required for draining is approximately 15% less than the capacity of the hydraulic circuit.
So for a total capacity of 8L, you will need 7L of oil maximum to drain. The proportion of remaining oil is identical to that of an engine (for which the oil pan is not dismantled).
Of course if elements have been dismantled you will need to provide more oil.
Some older automatic transmissions (e.g. Mercedes) have a plug on the torque converter, which allows a more complete drain.

What oil to put in the automatic transmission?

The automatic transmission, through its technology, is a very sensitive component to the quality of oil used.
It is imperative to follow the recommendations of the box manufacturer.
Improper product or inversion may destroy the box.
Never add oil additives or cleaners which can cause serious malfunctions.

BVA drain common errors:

1 - Wanting to rinse everything at all costs:

In all mechanical parts there remains oil, particularly in the engine which also has a complex oil circuit.
This does not mean that we are going to flush the engine at every oil change.
All the manufacturer's procedures indicate to drain by gravity and there is never a question of rinsing everything or using an emptying machine. But if you want to, here's a tip to empty everything without additional dismantling.

2 - Additives and cleaners:

These products are prohibited by transmission manufacturers because they unbalance the oil formulation and cause damage.
The additives added to the oil are real poisons.

3 - Diagnostic device:

Resetting a BVA is not recommended because the transmission will lose its self-adaptation history and "believe" itself to be new, which causes jerks in operation. For temperature measurement, there is a tolerance of 10 to 15°; a simple thermometer is sufficient.

4 - Oil level accuracy:

As for the engine, the level can be done to within 0.5L.

5 - You must be a highly qualified specialist:

You don't need a doctorate to empty a crankcase, change a filter and check the oil level.

Drain an automatic transmission by ZF:

There is a very simple trick to drain everything (if you really want to):

Once everything has been dismantled, swallow new oil with the tube (cut and cleaned beforehand) from the old filter. The oil will fall through the return of the exchanger, you just have to wait for it to arrive clean.

A video example >here

But you have to be very careful and be able to stop the motor immediately when the level is low in the container. Provide a large receptacle!

It's very simple, the suction pipe in its original location. The discharge will be done through the BVA housing, hence the need to have a basin a little wider than the housing so as not to get oil everywhere. There is no dismantling of fittings or anything else to do.