I have a 89 Sierra and for some reason, every time I get to about 20-25 mph it will not shift into 2nd gear. I checked my tranny fluid and added 5 quarts. I measured it after this and it seems to be at the correct level. Now I can smash the gas pedal and it will rev till it can't no more. Can someone please help me out!

 

Added 5 qts?

 

Sorry if I didn't make that clear. I was told that I needed to put 5 quarts of auto tranny fluid in there to fill it full. I am almost positive 5 quarts is the correct measurement but I could be mistaken.

 

did you buy it that way or is it leaking?