My son and his wife bought a new C4 Citroen diesel automatic a few months ago. It seems very nice, but when I drove it I noticed the strange gear change. It drops down the revs and almost feels as if it goes into neutral before it picks up the next gear. All this happens without lifting the foot off the accelerator. It feels like a very smooth and slow manual change. Is this normal for these vehicles?
The Citroen has an automated manual gearbox, which means it is a manual gearbox with an automated shift mechanism, and what you're feeling is exactly what you describe, a smooth, slow manual change. It sounds normal.