My 2007 535I (automatic trans) is starting to have very rough shifting. I have had great success with Lucas shift stop additive. But I cannot figure out how to add it unless I drop the pan/filter. Is this my only option for adding? And should I add the Lucas or just add trans fluid.

 

If you're having shifting issues you should just fix the problem. 4 cylinder sleeves and a bridge seal with new fluid will get you right. Are you leaking fluid? If not there's no reason to add any you're just over filling it. The fill plug is on the driver side of the transmission. How are you dropping the pan but don't know where the fill plug is. More than likely it's not filled correctly if that's how you're adding fluid. Also no need for any Lucas in these transmissions. They are tanks and need the correct type of fluid at the proper amount