904 transmission shifting adjustments

I see a few problem areas. Yes, the car needs to have actual functioning throttle pressure (Kickdown) linkage. It controls when it upshifts and downshifts as well as how hard it shifts.
There is a fat spring in between the valve body and trans case. This "accumulator spring" softens the line pressure between shifts. Toss it out. Finally, you can raise the line pressure to firm up shifts. It is an allen hex screw above the valve body on the drivers side. You can google search for Torqueflite shift improvement tips and see pictures on what I mentioned. FREE adjustments like this are great. You can thank Rick Ehrenberg from Mopar Action magazine for that one.
Also, the traction bars.....Not needed nor helpful with a Mopar. The design of the Mopar leaf springs is not like a Chevy or Ford. Our cars have stiffer front sections of the springs and the traction bars are just dead weight.