transmission slippage

The automatic transmission on my 1993 Ford Thunderbird, 100k miles, under these conditions:

After vehicle has cooled off only
Only when taking off from a stopped position
Only briefly(1-two seconds).

So for instance, I start it up in the morning put into reverse(never a problem) back out and put it in drive. It might or might not slip for about 1-2 seconds. Then it will not happen again if it is warmed up. I have checked the Transmission fluid and it is ok. No other symtoms. This has been happening for about one month.

Any ideas? Is this the end?

Service the transmission by dropping the pan and cleaning it out, change the filter, reassembling it and flushing the cooler line. If you have a mechanic do this, make sure they clean and leave the magnet in the pan (they usually throw them away, a bad idea. ) You should be doing this service every 2 years or so.
In my expereince, this cures a slipping trans about half the time. If the problem persists, a rebuild may be in order.

Add more fluid, if that does not help, suspect a small crack developing in the fwd clutch - which is a common problem with this car