2002 Winstar. 3.8 liter engine. Makes a straining, moaning noise under hood when I floor it up an entrance ramp. Starts at 4500 rpm. Stops after it shifts to a higher gear.
No other problems. No dash lights. No leaking fluids.
Didn't notice it until I tried to sell car and test driver got into it up the entrance ramp.
Two mechanics said it wasn't transmission. One said it sounded like an air flow problem and replaced air filter to no avail.