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Hi, I'm a new Polo user, and just got a 1.4 with automatic transmission (2nd hand, 2002 made).

Noticed some 'strange' behavior with the automatic gearbox :

1. If the car is in 1st, 2nd and 3rd gear, whenever I release the gas pedal, the engine speed will drop close to idle, and the car will basically feel 'rolling free' very smoothly. If I accerlerate again, the engine will simply rev up to the necessary speed.

2. However, if the car is on the 4th gear, usually travelling at close to 60mph, if I release the gas pedal, the engine will not drop to idle. It seems the engine is now 'locked' to the wheels, just like a normal manual transmission. Since the car is now off the gas, the engine speed will drop by around 500rpm, and the car will feel being pulled back suddenly (just like what will happen with a MT at 1st or 2nd gear). Although such engine brake is not very apparent, I'm not sure why the huge difference from the first 3 gears, and if it is a problem with the AT.

Anybody knows if this is normal?

Hi Kitsiu, and welcome,

I don't know the Mk6 auto-boxes very well, but I can tell you the following;

On the Gf's Mk3 Golf, the box 'sticks' in all the gears, not just in the top one. So if you let go of the accelerator pedal it won't drop to idle but instead it slowly drops off the revs. If you touch the brakes, then it *will* drop to idle (or near that) right away.

On my dad's Toyota Camry, it lets go of the revs all the time, in every gear.

I think it's just a matter of how they've programmed the box, but if you're worried you can have it checked using VAG-COM or through the dealership (have them take a test drive).

HTH!

That's what you call lock-up.

Just like manual transmission cars, cars with automatic transmissions need a way to let the engine turn while the wheels and gears in the transmission come to a stop. Manual transmission cars use a clutch, which completely disconnects the engine from the transmission. Automatic transmission cars use a torque converter.
A torque converter is a type of fluid coupling, which allows the engine to spin somewhat independently of the transmission. If the engine is turning slowly, such as when the car is idling at a stoplight, the amount of torque passed through the torque converter is very small, so keeping the car still requires only a light pressure on the brake pedal.
If you were to step on the gas pedal while the car is stopped, you would have to press harder on the brake to keep the car from moving. This is because when you step on the gas, the engine speeds up and pumps more fluid into the torque converter, causing more torque to be transmitted to the wheels.
At higher speeds, the transmission catches up to the engine, eventually moving at almost the same speed. Ideally, though, the transmission would move at exactly the same speed as the engine, because this difference in speed wastes power. This is part of the reason why cars with automatic transmissions get worse gas mileage than cars with manual transmissions.
To counter this effect, some cars have a torque converter with a lockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slippage and improving efficiency.
And because the gearbox cannot slip anymore the engine-rev's will drop simultaneously with the gearbox.

Get it ?

Thanks guys. I guess I'll just bring it to the dealer for a check, just ot make sure it is okay.