2005 Aveo Automatic won't shift to 4th gear

[Inza]

My car smoothly shifts until around 50 mph, RPMs go up to just about 5, but won't shift up. Tried speeding up to as high as 70 mph, tried tapping brakes, let off gas, tried again, turned car off, tried again. The engine has 79,696 miles on it. Any suggestions.

[Thymeclock]

My car smoothly shifts until around 50 mph, RPMs go up to just about 5, but won't shift up. Tried speeding up to as high as 70 mph, tried tapping brakes, let off gas, tried again, turned car off, tried again. The engine has 79,696 miles on it. Any suggestions.

Is it an automatic transmission?

[petrified.rabbit]

i love that you asked if it was an automatic.

Any CEL? lights i don't know if the car should shift past 50, or if that is the torque converter locking.

[Thymeclock]

i love that you asked if it was an automatic.

Any CEL? lights i don't know if the car should shift past 50, or if that is the torque converter locking.

I love that you didn't ask why it was running at 5K RPM.

Obviously it should have shifted into high gear and/or entered TC lockup before 50 MPH.

How does the transmission fluid look?