92 F350 transmission
 

I just went and picked up my new truck in michigan and while driving it seems like its searching kicking back and forth between gears but it wasnt goin between 3rd and 4th like i thought doesn't matter if it was at 55 or 75 out on the expressway. Could the torque converter be locking in and out that makes it surge like this? And yes i checked the fluid and its full and smells good not burnt. Thats you can hear it rev slighty but not the huge jump when you kick it out of overdrive. im new to automatics. Its a 92 F350 crewcab dually 2wd 198k miles with a reman engine. Need some help here Thanks Dave.