Transmission does not shift past third gear

FKHAN77

MEMBER
2007 CHEVROLET LUMINA
3.6L
6 CYL
2WD
AUTOMATIC
250,000 MILES

Hi, My name is Feroz and I am from Dubai, UAE and I own the car listed above.

When I drive the automatic gear is not changing after third gear. I think and I can see the RPM meter is going high if I increase the speed.

The gear oil was changed 50,000 kilometers before, so can you please advise what should be the problem?

Do I just need to change the gear oil and filter?

When I checked with a technician they say if you change the gear oil it should be fine and need to reset through computer system or do overhauling.

Regards,
Feroz

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,895 POSTS

Hi Feroz from Dubai,

Is this car OBD2? if so lets run the codes to see what comes up because you may have a turbine speed sensor that has gone out. Here is a guide to get us started and the location of the sensor in the diagrams below. Also a service for the transmission never hurts. here is a guide for that as well:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Check out the diagrams (below). Please let us know what you find.

Image (Click to make bigger)