For what it'* worth, when the tranny on my '93 SSEi had a TCC problem and wouldn't go into 4th gear when the engine was warm, there was no SES light but there was a stored error code for the TCC. It was code 32 or 36 or something like that.
That car had a rebuilt tranny that wasn't very old when I bought it, so I was surprised that it had a problem, but the fact remains that it did.
When I took it to the tranny shop, they looked-up the numbers from the sticker on the rebuilt tranny and said that it wasn't even the right version for the SSEi. They said there were at least 3 different versions to choose from.
So I had them replace it with a GM SRTA unit and haven't had a problem since then - that was 4 years ago.
I hope yours is a less costly problem such as the ECM or wiring...mine cost me $2,500!
'99 Bonneville SLE, white, 112,000 miles
'02 Park Avenue Ultra, white diamond pearl, 88,000 miles