Testiment to the 904 Trans

/6 Dan was really close on this, but just a detail or two more if I may.

It slips cold because the rubber seals are getting hard and unflexable until they get warm.
New fluid will kill a trans that has burned friction discs because the new detergents will disolve the adhesives that hold the clutch material to the discs.
Some converters have a drain plug so you don't have to pull it to drain it.

If it was my trans, I'd spend for all new fluid and a filter and see what happens.
Worst thing that could happen is that it would need rebuilt, and if it was so close that the new fluid killed it then it needed it REALLY soon anyway. Right?

Just the slipping when cold tells us that it's not long for this life anyway.