1superchevy

Just cant figure it out when the going normal and when the trans goes to shift from 2nd to 3rd it shifts at 30 normal then at 35 it does some weird shift on its own into what ever gear then it just goes back to 3rd at 40 and works normal every other gear. Then getting on the highway at about that speed and punch it and it just revvs all the way up and i have to let off for it to shift. I had it rebuilt and it still did it. then I just had the sun shell replaced from the last rebuild because it broke and chunks of metal were in there and now its still doing it. the vss and throttle sensor and wiring harness and everything else was check and i dont know what else to check now could it be my engine instead of my transmission or something electrical????? HELP PLEASE!!!!!!! its been 3 months with my car on the racks tired or I-4 want..car......back.

WILWAXU

iTrader: (6)

I'd check the speed sensor first. It's on the tailshaft and the plug should be pointed down. If it's turn to the side, it could cause the issues your talking about.

If that's ok, might want to check the tuning (shift points).

1superchevy

thanks for replying can it just change its own tuning like that because i have never had the tuning messed with it was stock when it started. Do you think maybe the torque converter. Speed sensor it in right position and the tuning will have to wait because i dont have a tuner.