91 Dodge Ramcharger shifting irregularities

[spares]

I have a 1991 Dodge Ramcharger, 5.2L, (318) V8, 4 Speed (O.D.) AMT. I have had this truck since it was built. I special ordered it and picked it up with 7 miles on it. I have taken great care of it, getting it lubed and changing all the fluids on a regular basis. Granted, my truck has 126000 miles, but it has always been very reliable and dependable, but lately it has started to shift hard.

When increasing speed gradually, it shifts out of first at ~23mph on the speedometer (don't know specific RPM), and roughly the same reading when decreasing (~25mph). It shifts into third at ~40mph and then fourth (O.D.) at ~43mph. It does not shift as hard when I increase speed rapidly, and it shifts into 4th at a relatively higher speed (~50-60mph) depending on how fast I am accelerating. In addition, when braking, it intermittently downshifts hard and when coming to a stop, just as I am about to be completely stopped, the truck LURCHES backwards, more like it settles very hard) right at the end of my stopping period.

The worst thing of all is how hard it is shifting. It bothers me that it may be seriously hurting my truck.

I may have a bad TPS, not sure if that can affect it, but I am planning on changing it to see if that helps or hurts. Also, my cruise control is tango uniform (TU) these days. Been a while since I used it, so I don’t really know how long it has been inoperable. My engine codes say I have a short in the speed control, and again, I am not sure if that can cause any or all.

Please advise.

Thanks