OK, sorry i'm a newb on this stuff but bear with me i'm usually a GM guy

1993 W350 5spd

here's my dilema.

speedometer is 10mph fast across the board, but the odometer clocks correctly.. are they run separate? or off the same signal.. how would i look into fixing this

 

Should be off the same signal I would think. Not really my area though. Someone should be able to help you though.

 

they are off the same line, sounds liek you need the gear that goes inside the trans.

look under the truck(driver side of trans) you will see a line that goes to the front of the truck (one round casing, covering the plastic spindle) see if that is loose.