I used to have a Renault Laguna (model year 2000) until I got a Volvo V70 (model year 2006) to replace it. One of the things that annoyed me somewhat about the Renault was that, if I was e.g. approaching a red light, I couldn't "pre-shift" into first gear from any higher gear before the car had come to a full stop or possibly very close to a full stop, even if I knew for a fact that I would need first gear going forward. (Note: I sold the Renault several years ago, so the exact details are slightly hazy. However, the general gist is correct.)
Now, I understand why I wouldn't be able to shift normally into a different gear while the car is moving without disconnecting the engine from the rest of the drive train by depressing the clutch pedal. That makes sense given even what little I know about cars, and is not what I'm asking about here.
Rather, I am curious why the Renault wanted me to bring the car to a full stop before I could shift normally into first gear specifically. (I don't think I ever tried it with reverse, and don't recall ever having any difficulty shifting into any gear.)
Volvo obviously managed to make the same thing work a few years later, and it doesn't seem like rocket science. After all, it's a required feature for all other forward gears to be able to shift into them while the car is moving, and a model year 2000 car is hardly an antique.
Is the Volvo lacking some protective mechanism that the Renault had (in other words, it's a kind of safety feature of the Renault, to prevent shifting into first gear at wildly inappropriate speeds whereas Volvo decided to trust the driver), or does the Volvo have something that the Renault didn't (which enables shifting into first gear while the car is moving)? What is the specific difference that could describe this behavior?