97 altima will not switch gears.

Hello, my 1997 Altima will not switch gears at a certain mph's, usually around the 40-60 mph range. I've taken it to transmission specialist, and they confirmed that it was not the tranny. I also took it to another motorist specialist, and they thought it was the vechicle speed sensor, but it wasn't.

...If anyone have any suggestions or have been in a similar situation, I really need your help....Thanks in advance.

im not really sure what youre trying to find out, is the car not upshifting or downshifting when at those rpms? if you slam the gas at 40mph in the altima, itll put you in 2nd gear around 3krpm, and it wont downshift from there. i'm not sure if i answered your question, and im pretty sure it didnt, but if you can specify upshifting or downshifting that would help me help you lol

Could be a problem with linkage.

Could be a problem with linkage.
There is a part in the dash called a Reed switch that translates the signal from the speed sensor and sends a signal to the transmission computer telling it how fast the car is going. The transmission computer won't show a code because it has no way to know how fast the car is going and compare it to the signal. Maybe it is diagnosed by using a scanner and comparing the signal to the speedometer.