The Transmission is a Rebuilt Jasper 1995 4L60E with about 2K miles and has been working great with nice firm shifts. Last night I was leaving work and I noticed that it was not shifting from 2nd gear. It takes off in 2nd and stays in 2nd. No slip to 3/4 or anything. I have reverse and manuel 1st and 2nd. No auto 1st and no 3/4. This morning it shifted 1-2, 2-3 and 3-4 a few times just great and then started having 2nd only. No slipping in 2nd and no problems untill last night.

 

Sounds like limp mode. But gnerally that would mean a 3rd gear start not second and you would always be in third. This may be and electrical problem you should have the car scanned for codes first.