shifting probs in 94 bonneville

[kague]

When the car is cold no problems..when the engine gets hot though it does not shift correctly into 2nd, 3rd and 4th gears. It goes but shudders and bucks...

From reading consumereports I think this may be a shift solenoid problem? Does this sound right? If so, what price tag are we looking at for repairs.

Any other ideas of what could be the problem?

ETA: there are no warning lights or check engine lights on.

[GTP Dad]

Try a can of Sea Foam or other high quality transmission additive. This will sometimes clear the gunk out of the valves and cure the problem.

[Hansnet]

http://www.putfile.com/media.php?n=1-2-shift

look/sound like that?