Nissan Repair: 98 Nissan Maxima hard shift while cold, nissan maxima, nissan cars

Question
Our daughter recently purchased:'98 Nissan Maxima & within a month she's noticed it shifting hard; more prominent at 'first' run-times(outside temp not cold)then gets better once 'warm'. Check engine light has not come on. She's been told it may be a knock sensor - is this a possibility with a 'cold' hard  shift? Also, what is a 'servo', and can it be related? Please help - she's young,expecting,works,& broke - she needs the car without getting reamed! "Thanks"!!

Answer
Kay,

The computer is known to have a problem as does the valve body when thngs are cold.  You could just change the fluid and see if that aids in the shifting.  When the fluid gets warm the problem is much less.  Fresh fluid should calm things down.  If not, you will need to take it to a shop that does Nissan cars.  They have a scanner to read what is going on while it shifts.  But, for certain change the fluid first.  The car has a drain plug on the pan and a screen for a filter.  So, there is no reason to drop the pan.  Just drain the fluid and replace it.  Usually takes four and a half quarts.  Put in four and start the car and run it through the gears while parked.  In park at idle check the fluid.  Add until you get to the cold fill mark and you are done.