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My transmission is starting to slip with I turn left, I've had this problem before, and it just needed fluid, so thats what I did this time, I've put about 1.5 quarts in it in the last 3 days and the fluid level is good and it still slips, any ideas on what could be the problem?

it's your wheels that are slipping on the ice!

Seriously though, was the fluid checked again after you added fluid AND while the car was both hot and on a level surface?
If not, then it may not have been filled enough in the first place or enough could have leaked out since adding fluid to cause the slippage .

If it has been checked again, as above, then tell us if it slips in all gears, 1st gear only, etc. and if the service engine light is on or not.

Did you check the modulator vacuum hoses and lines?
If the modulator isn't working right, shifting won't occur when it's supposed to.

Fluid was checked several times before and after filling on level surfaces. It does slip in all gears when making left hand turns and only left turns. The check engine light came on several days ago, and it threw a code for the evap system and they told me basically it has a small leak where the gas evaporates from the tank but it wont effect anything else on the car. it was reset and has not came on since.

Could be many things...what's the mileage? How often has it been serviced? When's the last time you did a drain and fill with filter?

ChilinMichael wrote:Could be many things...what's the mileage? How often has it been serviced? When's the last time you did a drain and fill with filter?

Indeed, a clogged filter will cause slippage and a fluid plus filter change is the cheapest of possible repairs.

As I mentioned earlier, I would be sure to check the transmission vacuum modulator hose and plastic line for cracks.
Even if the line and hose are OK, the modulator can still be bad.
You can take the hose off, turn it so the hose connector faces downward and if any transmission fluid comes out, it is bad.