type dougie "Again I wasn't sure how the tapping side to side was supposed to work."

First off the lever should be centered with equal movement left- and right+. You should not have to hold the lever to either the - or + to maintain a gear selection.

Tapping the lever to the left- reduces the transmissions range by one but it will not shift if the RPM is too high and damage would occur. That is one example of the shift being limited and the actual gear the transmission is engaged could be different than what the instrument cluster shows. The instrument cluster shows the shift range selected, but not the actual gear the transmission is in. You manual limit the range of the transmission when you tap the lever left, so if you are in 5 going 140 mph and you tap left twice the transmission will be in a 1,2,3 gear range, but it wont go into 3 until those rpms and vehicle speed will allow it with out damaging or loss of control. When you hold the selector to the left- the currently engaged gear in range "D" is indicated in the instrument cluster and the shift range is limited to that gear. Tapping the lever + one time after another increases the range with each tap, but the transmission may not upshift to the gear selected because the vehicle speed and engine rpm simple don't match. Going ten mph in 4 gear won't work. Tapping the selector and holding it to the right + will place the transmission back in "D". Tapping the lever left or right selects the transmission range, not the gear. Hope that makes sense.

From your description it sounds like a problem in the SLA (shift lever assembly). They are not serviceable, but need replacement if not working properly.

Also the selector is very sensitive. You can not keep your hand on it like you would with a standard shift/clutch transmission! With the automatic transmission and using the gear range selection + or - I rest my hand on the console and flick the lever with my thumb or index depending if it is an up or down shift. Body weight movement in the car is enough to move the lever and change shift range even though you haven't knowingly moved your hand.