Trans shift

I have a 1998 Buick Century Custom and when the car is cold it shifts all the way to overdrive perfect, for about 2 take offs it works fine, but once it gets hot , I take off and it will not come out of first. I replaced the modulator but that didnt seem to fix the problems....any help would be great.

Are you using the right type of fluid or is it full .

The fluid is full. It does smell a little burnt, but I thought that's probably because we couldn't shift out of 1st all the way home.

Would the temperature sensor cause this problem?

Just to let anyone who might have the same problem....it was the trottle control sensor.
nctim1

:grinyes::grinyes:

Just to let anyone who might have the same problem....it was the trottle control sensor.
nctim1

:grinyes::grinyes:
How was this determined, by scan or cel on, or testing with an ohmeter?

scan