Automatic Transmission Issue?

[chevytruckman]

Hey guys, I've had a bit of an issue with my transmission. To be honest I don't know what kind it is but I have a 2004 Silverado and it's an automatic. I'll do my best to explain the problem. In the morning when you start it, when you hit about 10mph the truck pulls or it fells like to when you slow down and then you slightly accelerate for one second . But after that it's a smooth shifting transmission and it doesn't do that at all after you drive for an extended period of time. It only seems to a problem after you park the truck over long periods of time, like when you come home from work and don't use it until the next morning. I had a transmission flush and filter change done to it but it's still the same. I would appreciate any help I can get.
Thanks.

[Jimmiee]

I've read your explanation 3 times and I don't understand what you are trying to say? What do you mean the truck pulls?

[chevytruckman]

It's like the transmission is not smooth threw all the shifts, threw the first shift between 10mph and 20mph you can feel when the trasmission shifts. I guess the best way I can explain it is if you turn on the truck and floor it, it's not going to be smooth threw the first shift. There will be a slight delay when you reach 20mph and you feel it thru the entire truck and then it rides just fine thru the rest of the shifts. It's like when you reach 20mph you slightly tap the brakes and then you just keep accelerating. If you come to a red light like a mile down the road and stop and then you continue when it turns green you feel it less. I guess you gotta let the transmission warm up or something?

[Jimmiee]

What might be happening is the transmission is in failsafe and the PCM has raised the line pressure which makes the 1-2 shift very firm. Drop by Autozone and get it scanned for codes would be my suggestion at this point.