I got my tranny rebuilt a year ago and when i go to pass sometimes i floor my car and my car revs up but wont get any forwared moentum then it shifyts hard then i go any ideas whait it could be...

 

Check your fluid to see if it's burnt. Off the top of my head is sounds like your clutches are toast (the engine winds up with no increase in speed.)

The clutches are not engaging fast enough or slipping. A problem in the valve body can also cause clutches to misbahave.

Either the fluid is the best place to start. It should be a nice color red (not dark)

 

Fluid is fine btu the tranny shop says nothings wrong bla bla bl even tho i know there is

 

You might want to try to take it to another shop to see if they have a different opinion. Otherwise, you might want to drop the pan and see what is going on in there. Is this problem consistant in all the gears? 4>3, 3>2, 2>1?

Does it slip, or race freely then grab between the downshifts? Or does it race then slip in to the lower gear?

 

I only happens when i floor the car to pass and it revs up but it dosnet awalys do it

 

Tough call. Sounds like a sticy valve or solinoid (sp?) to me. Try to see if there is a corelation with temprature. Winter months may worsen this problem.