Can someone give me an idea what could be wrong with my overdrive?

It does not work and I have performed the following procedures.

1990 Volvo 240 wagon with 224 K miles.

1) I have changed the overdrive solenoid with a brand new one.

2) When I press the overdrive switch on the shifter, I hear the relay click and the light comes on/off in the dash. I also hear a clicking on the solenoid that I replace under the car.

3) Before I changed the solenoid, I checked the voltage at the solenoid and was getting 12 volts.

I did a road test after changing the solenoid and it does not appear to be working. The car shifts gears fine, but when the car speed is around 40-45 I don't feel the car shift again. I can drive the car up to about 70 MPH and the engine revs really high like it needs to shift gears. If I click the shifter button nothing happens with the transmission.

Please correct me if I'm wrong here...

The car starts in 1st gear from a stand-still, then I feel it shift into second gear around 10-15 mph, then it goes into third around 25-30 mph.

After that it does not shift again.

Is my transmission a 3 speed with a OD for the forth gear?

I have not changed the transmission oil or filter since I bought the car in April. But the OD has never worked for me. The Transmission oil level is full and it's not leaking any oil.

Thanks for any help you can provide.