Worn or damaged front seal, worn or damaged torqueconverter hub, worn or damaged torqueconverter hub bushing. Worn or damaged torqueconverter hub bushing will sometimes damage the input stator which requires disassembly of the transaxle assembly.
Ford windstar
seal. expensive
Transmission fluid is low, dirty filter, leaking seals, sticking accumulator, etc.
The Windstar transmission could have a seal that leaks worse as the transmission gets hot and the fluid is under pressure. Go to a car wash and clean the transmission good. Watch for several days to see where the fluid is leaking from so that you can find and fix the leak.
According to the 2001 Ford Windstar Owner Guide : ( Motorcraft MERCON-V is used in the automatic transaxle / transmission )
Motorcraft MERCON automatic transmission fluid in the 1999 Ford Windstar power steering ( according to the Owner Guide )
Check or change transmission fluid and filter
You might need transmission fluid !?!?
transmission cooler
There are several reasons that can cause your Ford Windstar to jump when you give it gas. The most common reason is a problem with the transmission. Check the transmission fluid and make sure it is at the full mark.
It could be caused by low transmission fluid level, dirty transmission fluid, a faulty torque converter clutch solenoid valve, or an internal transmission mechanical problem. Try dropping the transmission pan and changing the transmission oil filter and transmission fluid.
If too much transmission fluid is added, or there is something wrong with the pump