91 Ford Explorer Transmission Problem

Hi all,

My '91 Ford Explorer is having some transmission problems.

I noticed over the past couple months that when I shift from 'park' to
'O' that it took the transmission a second or two to engage instead on
engaging instantly.

Then the other day I was driving and while pulling out into the street
and merging with traffic then transmission dis-engaged from the engine
and the engine rpm increased. I downshifted into the '2' gear and the
transmission re-engaged. I headed back home because of this and then the
tranamission disengaged again from the '2' gear. I shifted again to the
'1' gear where I slowly drove back home.

Anyone know what may be the problem? Are there any adjustments I can
make or does it sound like I am screwed and need another one?

Mike