Automatic Tranny Question

Hi,

I've got a '92 Buick Century Ltd. V6 3.3L.
My car has P R N (D) D 2 1 on dash.

I want to know if my car has 3 or 4 speeds and what type of transmission I have got (Hydra-Matic 3T40 or 4T60-E).

Thank you.

How many forward speeds do you have? That will answer your question! The 3T is a 3 speed and the 4T is a 4 speed! It can also be a 4T60 same trans as the 60E except the 60E is electronically controlled.

This is my question.

For the answer I have to go under the car to see the tranny ID tag.

1st speed is until 20 km/h.
2nd 'til 40km/h.
At 80 km/h seems to me that it's shifting again but could be because of Lock-up Solenoid. In this case is 3-speed.
Or is the 4th speed.

That's why I asked someone who knows the year and engine of the car, for an answer.
On dash I've got P N R (D) D 2 1.

It looks like there are 3 speeds and Over-Drive, but I want to be sure.

By the way what is this Over-Drive?

Now is for the first time when I'm driving an automatic. For 12 years I drove a standard.

Thanks.

transmissions run use gearing ratios to make the load on the engine easier from a start. for simplicity's sake, the ratios may be as follows:

1st: 3:1
2nd:2:1
3rd:1:1
4th: 0.5:1

the first # is how many times the engine spins, per the second number, how fast the tranny spins. Overdrive lets the tranny spin faster then the engine.