torque converter clutch issues?

[lost86broncoii]

Hey guys, i had my transmission acting funny a few months ago and snapped my driveshaft cause of it.... it was never fixed but kinda went away for a week or two. Here's whats going on when i first start driving my rpms get to 3.5-4000 before the tranny shifts and when driving i notice my rpms going up and down kinda like the tranny was slipping just a little bit like from 2,500 to 2,200 then right back up again with a little kinda like surge.. is this caused by the TC going out on me? my gas mileage is down to like 14mpg :-P and the truck seems alot slower? wondering if i could get the tranny to last the winter at least then swap in a 5-speed :-D any one got suggestions a friends recommended lucas oil tranny fix fluid not sure on the real name exactly lol. thanks for any suggestions or help.

86 bronco ii 4x4 A/T 91k miles