Loud whine then knock in overdrive

Well, without hearing the noise myself, i could guess that the torque converter clutch might be going bad. the torque converter is the part that transfers the power from the engine to the transmission via viscous fluid motion, the converter also has a clutch that internally provides a direct connection inside the converter for better fuel economy. but as with anything labeled as a clutch, it wears down to a point where is slips. the noise your hear could be the torque converter clutch slipping. i owned a 90 astro van with the same drivetrain that made a noise similar to what you speak of up hills. while driving up hills, fully depress the accelerator and if the clunking noise occurs, then the whine goes away as you accelerate faster in a lower gear, very likely this is the case. you would have to have a transmission shop diagnose further. i drove that old van for five more years cause i didn't want to pay to have transmission repaired. it can be very expensive.