While driving in the city the transmission shifts good from 1st to 2nd but stays in the gear. It only shifts to 3rd and 4th while driving on the highway. It'll shift to 3rd when I reach 40 mph. Did I do something wrong on rebuilding it?

 

It's a A670 3 speed transmission. I put a transgo shift kit in it while rebuilding it. And these symptoms are still there. It want shift to 3rd until I reach 40-50 mph. While driving around town I'm always in 2nd gear. Can anyone help?

 

Are there any techs on here that can help me with this problem

 

It's possible you have the kickdown linkage out of adjustment. That linkage being out of adjustment will cause it to hold 2nd gear until 40+mph as it makes the trans think you are applying more throttle than you actually are. It could also be a symptom of the shift kit.
IIRC to adjust the linkage, you loosen the nut on the spring loaded part at the trans, and let it move to it's natural resting position, then tighten it back up.

 

Glad you responded in time. I was about to take the valve body out with the shift kit and install my old Stock valve body. The linkage bracket on my transmission was slightly bent. It got that way during the installation process. Thanks Smoke. I didn't even think to look there

 

Welcome,
Have a LOT of experience with the 3.0/3-speed combo.
All else fails, swap it to an A543 5-speed manual. I did it on my car, never regretted it.