[Grandad#3]

Most gears are the 20 X 21 tooth count. Not that hard to change out, but a PITA to get to it. You have to remove the Steering Wheel (Disconnect the battery ground wire and let the car set for 45 min. to deactivate the Air Bag). Clark's garage.com has a good writeup on how to remove the dash trim as the Gage Cluster has to be pulled out to change the Odometer Gear.

http://www.clarks-garage.com/shop-manual/elect-07.htm

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=see_more&please_wait=N&db_record_number=71468&FILTER_9144=Y&FILTER_911E=Y&FILTER_911M=Y&FILTER_911L=Y&FILTER_996J=Y&FILTER_997M=Y&FILTER_986M=Y&FILTER_987M=Y&FILTER_987C=Y&FILTER_356M=Y&FILTER_944M=Y&FILTER_928M=Y&FILTER_PORS=Y

944 Odometer Gear Replacement

Cheers,
Larry