m311: hum, you got one heck of a deal....was an over/under at least?1? lol
rule out the transfer case as IA says...it can make it feel like you have lost your tranny, no lie!
I also reiterate what he said about throttle rod, TorqueFlites have no vacuum modulator like Ford & GM trannies 3 spds, so you can rule out those disconnected lines, but they depend on the throttle lever for proper line pressure, NOT just kickdown...
if it's poorly functioning, you are good at basic fabrication, and you care more about functionality than originality, i HIGHLY recommend you go to a junkyard and get the TorqueFlite throttle *cable* setup off a second gen Ram or Ram Van et al...I am just getting this mod finished up on my Eagle...it will fit on your AMC TorqueFlite just like it fits on the Mopar one and it has a very standard carburetor end that works with my Edelbrock 4V for example...I figured this out recently, and am still fine tuning the bracket at the carburetor on mine, but it's an easy mod, worth the 10 bucks it cost me so far....
onto the tranny, first thing you need to do is inspect the fluid that was in it....I recommend just getting a tranny filter kit and draining the tranny, any car that has been sitting surely needs it, and replace the fluid that comes out when you take the pan off...if it is real bad you should drain the torque converter, too....some TC's have plugs ,some have to be removed to be drained...cant remember for the A998, someone chime in?!?...
anyway if you're not familiar with automatic transmissions the fluid should be RED not brown, and should not have a burnt odor, but an almost sweet one, and it should not have an undue amount of metallic particles foating around in it
.....if you have an inch - lb torque wrench that does like 30-100 in-lb range, this is a good time to adjust your bands....the procedure is simple, but demands precision on your part....if not, new filter, new fluid filled to proper level, see where your at before you take it into a tranny shop to get the bands adjusted & the line pressure tested.