Help with 99 Grand Cherokee Tranny

Hello everyone...Does anyone know what I can do to stop my 99 Grand Jeep Cherokee Limited from shifting hard from first to second gear at a slow speed?  I tried to give it a quick learn and it worked for about 2 days then went back to its hard shift pattern.  I want a cheap inexpensive fix because I am selling it soon and I don't want to spend a ton of money on it.  I know that whoever gets the vehicle will complain about it so I might as well do it before they buy it.  It is extremely noticeable in a parking lot where speeds are slower.  The slower you go the more dramatic the shift pattern gets.  The faster you go, it's barely noticeable.  Any help would be greatly appreciated!

Thanks,

Gary