Gearbox Issue - 7 speed W204

[Marcellus]

My C220 has developed an issue with the gearbox.

It does this once per journey.

The first time I try to accelerate suddenly (pulling into a gap from a side road or into a gap onto a roundabout) it stutters from low speeds it stutters and bogs down.

However, if I repeat the same acceleration for a 2nd time there's absolutely no issue with instance response and pull.

It doesn't matter whether this acceleration is within the 1st or 20th mile of the journey.

If I drive gently then there are no issues it cycles through the gearbox quite happily.

I don't think its traction control related either as I switched this off, tested it and there are no lights shown on the dash board when it does it.

I did have the Transmission Fluid replaced about 5,000 miles ago in November and yesterday popped it back into the garage for them to recheck the levels which they said were OK so not sure if it's related to that.

Anyone any ideas on a solution or how to investigate further?

TIA

[Marcellus]

Just to close the loop on this, in case anyone else experiences the same…… it was the oil cooler

[5s Alive]

I'm surprised no one replied to your original post. How was the oil cooler causing the problem?

[Marcellus]

I was too, as I understood it one of the flanges had started to corrode, so when there was no pressure everything was ok, however under load and oil pressure increased it started to spurt out and caused a drop in pressure which the various sensors picked up, put car into limp mode reduced oil pressure car goes back to normal and all was good.

So on a motorway increasing speed from 50 to 69.5 mph no real increase in pressure needed but from 0 to 10mph more pressure needed so the issue.

[5s Alive]

Gearbox problems can often be caused by apparently unrelated components. My A4 developed some odd hesitancy when pulling away, it felt like slippage in the multitrionic (cvt) gearbox sometimes. It turned out to be a faulty engine coolant sensor which was an easy DIY fix. There had been a recall issued in the USA for just this problem but nothing in Europe. It was a common failure.