Transmission problem
After fixing the cruise control and other issues, Now i have a new issue with the transmission(inter mental problem).
When merging onto a busy road with full throttle or 3/4 throttle, the transmission wont shift up, it just keeps reving in first gear, until i remove my foot from the throttle and then re apply it, or hold the shift gate to the right. And when it does decide to upshift it shifts hard.
It shifts perfectly around town. Unless the engine is cold, it holds the first 2 gears long.
I have 87000 miles, 2001 C240, Behr radiator .
What could be causing this, would traction control stop it from upshifting even if the yellow light isn't flashing?



