Help: Auto Trans won't shift when cold in 5kt

["Pat Dooley" <pdooley@gte.net>]

Subject says it.
My 86 5kt(2WD) will not shift when cold.  I can let the car idle for 5-10
minutes in the morning and it shifts ok.  Otherwise, its drive around at
20-30 mph until things heat up enough to make the thing shift.  To make
things worse, it seems to be taking longer for it to start shifting every
day.

Somebody please tell me this not major trouble.  I have plans of installling
a 5spd, but not just yet.

Thanks, PSD.