1994 Sho ATX rebuilt tranny shifting problems

[Edward Birdsall]

I had my tranny rebuilt a year ago. Ever since, it never shifted properly. If I rug it from start or in drive at highway speeds, the rpms approach redline and never grabs the next gear either one down or one up in time to engage forward momentum. Why would this be? I love this forum. Any guidance is greatly appreciated. Thanks, Edward

 

[SHOdded]

Perhaps the VSS or perhaps incorrect fluid or insufficient fluid. Those would be my first ports of call. No codes in the ECU?