anyone know why after this last tranny rebuild my speeda is reading about 11mph below how fast Im actualy going ,nothing else was changed ,and could this affect my shifting, the builder did say he changed the drum in the tranny but I wouldnt think that woulf affect it ?

 

Hmm...maybe it was put back together with a different speedo gear on the drum.

Using something like the Dakota Digital speedo correction box might be an option.

 

Are we talking about a 4l60e? Unless he reflashed your computer your speedo should read fine. It might be a good idea to remove the sensor and make sure it was not damaged. Also inspect the connector for it. Vince B

 

seems like its gotten worse ,its about 20mph off now ,the tune is fine I checked it , would this affect my shift points because there a off also ?

 

It probably would. I'd pull the sensor and inspect it and the speedo gear inside the trani for damage. If everything inside looks alright, I'd try a new speed sensor.

BTW, the size of the error is not likely to be the same at various speeds. Just sayin.

Good luck.