1995 Gmc Sonoma Antilock Brake Light On, Speedo Don't Work, Tranny Don't

SHIFT HIGHER THAN SECOND, THIRD SPINS? 1995 GMC Sonoma 2 wheel drive automatic
Hi about three years ago I had my transmission rebuilt then about two years ago my antilock brake light came on and my Speedo stopped working. this is intermittent problem as when the light goes out my Speedo works. but when it don’t work the truck wont shift no higher than second gear, if I have it in 3rd or drive and it tries to shift in 3 the tranny just spins. The mechanic who rebuilt my tranny told me it was the speed sensor so I replaced it that didn’t help. About this last week I needed to get my truck going so when I got it started the light was off so I drove it but today after driving for about 20 minuets while sitting at a red light the antilock brake light came on and no speedo and no 3rd any suggestions

Find out why the Anti-lock light is coming on. I'm guessing that there is a wiring issue between the speed sensor and the ECM. If the ECM is getting erroneous information from the VSS due to bad wiring or connections, this is likely the reason why your tranny won't shift into 3rd, because the ECM won't let it. You could say at this point that perhaps the ECM is in 'limp-in' mode because it is not receiving correct signals. Time to start investigating. Good luck!