2001 Tundra 4.7 ext. cab. limited - Delay in Transmission at start; at times..

2001 Tundra 4.7 v-8 2-wd ext. cab. limited - Delay in Transmission at
start; at times..

Not sure why it's doing this... has been a great truck!
My first thought, is that it needs trans fluid... I went to the dealer for a
trans flush... and refill, and the problem is still there.... It usually
does this when the truck has been sitting for a full day or two. But this
morning, the damn thing reved up and wouldnt engage.... so I let off the gas,
and started giving it gas again.... 2x's... then it slamned into gear.... I
dont want to tear up something... yet I dont know what the problem is...
And this time, for the first time it did it twice to me while driving... once
it engaged, I drove to the first stop sign, stopped, and when I stepped on
the gas, the trans didnt engage, so I had to play with the gas, then it
slamned into gear... It doenst sound great when it does that... like I might
be doing more damage. I asked at the dealership, and they didnt know.
If anyone could help me out, I would appreciate it... Has anyone else had
this problem???
Thanks again!