tranny problems with 92 4x4

[sassee]

question................(and sorry for the long post)

My daughters' boyfriend has a 92 Durango that we got started again after sitting for 3 years. He has a Z-71 but this old truck was his Grandfathers so it has a lot of sentimental value. Anyway, it was parked and a rat made a mess out of the wiring under the hood. We spent all afternoon splicing wires and it cranked right up. Anyway, the reason it was parked was tranny. When you start off, it will hesitate and then slam into gear and go. Once it's going, it shifts absolutely fine! We drove it a few miles down the road speeding up and slowing down intentionally so the tranny would have to shift. I stopped and went from Park to Reverse several times fairly quickly and it would drive off fine but If I let it idle for a while in between the park and reverse cycle, it would hestitate and then slam into gear. I'm thinking bad pump. Anybody else want to way in???