so you dropped the pan to change the fluid??? does that mean that the 99 doesn't have a drain plug??? every AW4 i've worked on has had a drain plug in the bottom of the pan.
or did you also replace the filter in which case dropping the pan makes sense.
either way, it's not that hard. next time, make sure the bolt holding the dipstick tube is nice and tight, and seperate the dipstick tube at the joint (about 1/2way down the tube). then it's easier to drop the pan. after that, remove the bolt and take out the upper part of the tube. then after re-installing the pan, you put a new o-ring on the upper part of the tube, stick it back into the lower part of the tube that's still attached to the pan and give it a gentle tap until it's seated. then put the bolt back in to hold the upper tube in place.