well, we just need diagrams on the engine wiring harness and tranny. mainly about how the computer communicates with the engine and tranny.
Sounds like the speed information is not getting to the computer.
You need a 95 cluster and wiring to go with the 95 computer.
I am guessing that you are using the 95 PCM and engine wiring harness.
Is it a 4R70W or a E4OD transmission?
I'm not sure, it's a small transmission.