Dodge went electronic speedometer in the 1990-1993 trucks (and obviously newer years but not on topic). The 1993 speedo heads seems different in that access to the gears is not possible? Thse gears are sold new on ebay and fix most issues not VSS related.

so a speedo head from 1990-1993 will work in your case. Ive got a 1993 speedo head in my 1992 and its perfect after gears were changed, after I blew the circuit in the 1992 when the jumper wire slipped testing the circuit board. oops