Only switches from 1st to 2nd if I pump gas

Hello all.
My 94 Ford Explorer began to get stuck in first gear. When leaving a stop light, the transmission didn't slip but the RPMs continued to climb without switching gear. I figured out that if I wait until the RPMs get around 2000, I can quickly release the gas and slowly repress the gas pedal to get it to switch gears into 2nd. Above 2nd gear it is fine.

I also noticed that if climbing a steep hill or turning a sharp corner while under 25mph, the RPMs will suddenly jump real high until I depress the gas pedal and do the trick again. It just requires even more patience when in this situation vs driving on more flat of a surface.

So far I bled out all of the transmission fluid and replaced it with new clean F-type fluid. I did not however change the filter yet due to reading stories where people claim that their car got worse and they had to get rid of it due to the age/value and its just not worth getting a new transmission.

I've been driving with the new fluid and old filter for about four months now and the problem remains.

Any thoughts?
Thank you!
Rich

Update:
So apparently this is known as "Flairing" or "Flaring". For others searching the same subject, here's a great thread

http://www.explorerforum.com/forums/showthread.php?t=170632

This references another thread which shows step by step instructions with pics. You can see that thread here

http://www.explorerforum.com/forums/showthread.php?t=128800

Here's the specific section that seems to be where my problem lies

http://www.explorerforum.com/forums/showthread.php?t=140987

Hope this helps future users. If I continue to diagnose and attempt the repair, I will post more updates.

Thanks
Rich

Upon digging in: I found that the article I posted above is for cars newer than mine. I have a 94 Explorer 4WD 6cyl. That's for Explorers from 1996+

Why did you put type f fluid in that trans that should be mercon

first check the vacuum hose at the engine and at the pass side rear of trans just above the pan make sure it is connected and has vacuum although that would affect all shifts lets start there. Next this do you have any hardware to monitor pids with to see if the pcm is commanding the shift and its not shifting or its it not being commanded? I believe that is the intermediate band on that trans that performs second gear shift.

Jut looked at a manual that has a trans downshift cable also make sure that it is free and not stuck on pull it at the throttle and make sure it snaps right back and is not being held by the throttle. If you need to you can disconnect it at the trans and drive it to see if it makes a change. It only moves a 1/2 in or so and doesn't move at all till say half throttle roughly. buit is need to be free if it doesn't snap right back it wont work. I have seen the ball on the trans get rusty so it sticks on a little bit. If this is the case it will shift normal when disconnected from the trans just wont down shift when you get on it.