Hi Andras;
- and welcome! This is a great board for advice on Volvo repair and maintenance.

As you say the leak is "next to the engine right above the exhaust", my guess is that there is a hole in one of the two metal lines going to and from the radiator. These lines are held together by a bracket and may rub against eachother or the bracket to the point that a leak will occur. It is good preventive maintenance to put something rubber between these lines and the bracket.

When you don't see any smoke at high speeds, it could be that the wind is pressing the ATF along the lines and backwards rather than letting it drip on the exhaust.

I'd have a look in this area first.

Good luck,
Erling.
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