It will not up shift and speedometer not working?

CARL RODELA

MEMBER
2001 CHEVROLET BLAZER
6 CYL
4WD
AUTOMATIC
15,000 MILES

Had transmission rebuilt because it would not go in to reverse. Now it will not up shift and speedo not working. Was told it was a speed sensor. Replaced and it still is not working. Any suggestions as to what it might be so when I take it back (transmission work under warranty) I do not look like I have no idea what i'm talking about.

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

A transmission can have upshift issue with upshifting when it is low of fluid or the filter is plugged.
This can also be triggered by internal leaks in the valve body. If the pressure solenoid is faulty it can also not allow the transmission to upshift.

It is always a good idea to check the transmission fluid level anytime you have a shifting issue.

https://www.2carpros.com/articles/automatic-transmission-problems

Any time you take a vehicle to a shop just let them know what you are experiencing. That way they will have a clear idea of the issue and can diagnose accordingly.
Any shop that rebuilds transmission should be able to diagnose the issue and do the appropriate repairs.

Please let me know of any questions.
Thank you.

Image (Click to make bigger)