I just got a 93 D350 innercooler 5 speed getrag 4x2 the speedometer did not work when i got it (nothing was there but the housing in the transmission) so i got a new sending unit from napa and when i am running about 45-50mph it reads 90+mph. the miles roll over super fast too. on a trip thats 22 miles it showed 31 on trip meter. the dash unit reads smooth no jumping or bouncing. anyone know what i need to do?

the new sensor is for a 92 d350 all 93s show automatic unites so said napa

 

There is a ratio adapter there goes in the trans I am not sure where to get it but someone who knows better will chime in

 

is it one of the L shaped reducers?

 

Use the search feature and search for ratio adapter.