tranny trouble

wifes friend has a 1994 dodge caravan,4 speed automatic transmission 3.3 motor.
yesterday after dropping off her kid at school it would not get over 10 mile a hour on way across town, wouldnt even make it up a little hill on way there. she said it does fine in reverse.
any ideas on what this may be?
thanks

Not clear if it's transmission related or engine related. Need more info. Is it shifting through the gears? Is is jumping out of gear? Is it jumping to 2nd gear and staying there? Is the Service Engine or Check Engine light coming on.

Does it cough/stumble when she hits the gas? Does the engine run ok when in park both at idle and higher RPMs. What maintenance has been performed recently?

First step is to check for error codes. How? Turn the key from off to on (not start) three times leaving it on. Now count the flashes of the Check Engine Light. All codes are two digits. There is a short pause between digits, a longer pause between codes. Example: flash, flash, pause, flash is code 21. Code 55 means the reading is complete.