My transmission been shifting hard! Today i drove it without a battery and the transmission was shifting smoothly! Any body have an idea why?

Bad battery, poor battery connections (corrosion) etc. Some transmission functions on some vehicles are derived from battery voltage and not ordinarily from alternator voltage. Removing the battery forced it to run on bus voltage and not battery voltage. ...Show more

Year make and model.  TCM could be bad and it got reset without a battery. 

Driving without a battery is not recommended however.  You probably fried the ECU already.  If the car does not start next time, you know what to fix....Show more