Back in the early 90's Dodge went to a cable set up but before that it was a rod . Unless , like I said it was swapped out at one point in time . But judging from where this truck came from before you I doubt it was ever swapped to a cable . Either way it can be adjusted and the guy at the transmission shop "should" know how to adjust it . Hell , he should have already adjusted it because that's part of his job on the install . There should be a steel rod going from your carb ( drivers side ) down to the side of your transmission where your shifter linkage connects . The carb running rich could be anything from out of adjustment , in need of a tune up , in need of a rebuild , float to low , etc. .