Got a problem with my auto tranny. It won't shift out of 2nd until it's well warmed up. After it shifts the first time, it works fine and won't do it again unless the car sits for several hours. The problem has been getting worse lately. Checked the shift solenoids, they were ok. Changed the fluid, it looked fine, nothing dark or burnt. The car only has 100k on it. Any ideas what this might be???

 

It's probably your vacuum modulator. Usually when it goes bad you will want to replace it with a new one. Its the unit that sits on top of your tranny with a thin long vaccum hose that goes to the intake manifold. It regulates the shift solenoids, so when it isn't working properly that's when you start getting irregular shifting issues. Remember the mechanics behind shifting auto trannys, unlike manuals, are nothing but vacuum and electronics.