Did you actually replace a motor in the gimbal? Is that what you're saying? Looks like what I would call a "timing" thing. Something wasn't centered and lined up before it was dropped in its splines/gears.
Power on. Mark center(s). See what you need to do to center what you marked and re-do.
You may be able to do it with some trim adjustment in the correct channel but it's not the right way to fix it and you're going to lose a lot of working room on the short side if you do it that way. I doubt seriously there's enough trim to fix this anyway. It looks pretty serious. Trim is a fine-tuning thing.
I agree it looks off center in the pic it shouldn't be to the side that much,like you would see the landing great in your pick..also in the dji go app there are controller calibration settings that might help after the realign
Hey, check this new option that appeared in the latest 3.0.0 DJI GO app released today, might help you out, haven't tried it so I don't know what it does: