Vehicle 97 Expy, 5.4 XLT 2x4, air leveling and tow pkg.

Situation: installed TransGo SK E40D spring kit to cure 1st to 2nd hard shift. It did the trick and shifts great up to a point.

Issue: Now after replacing the springs, any and I mean any added load (mild incline, lane change) while in OD it will downshift, won't shift up unless going down hill and I'm sucking gas. 1st-3rd is great, but it will not stay in OD to save its life.

I believe the cure is to reinstall the old OD springs, but I don't know which set that is in the accumulator body? I also could be wrong and it may be something else I'm hoping someone can answer so I only have to do this once.
I have a friend who wants to buy it and I don't want to give him an issue or I may not have a friend for long.
I appreciate y'alls assistance.

Update: found the instructions, does anyone know if the 4th Accumulator piston is OD?

 

I don't think the problem is with the springs, the transmission itself cannot decide when to shift, up or down, the computer controlling the solenoids does. I think something else is going on like a TPS switch or MAP sensor, something that the computer uses to determine engine load.

I understand it happend after the shift kit but I just don't see how its related, its just a coincidence.

A good scanner with data capabilities will be the go to tool.

 

Appreciate your reply jk080, the main reason I was thinking it was the spring was because it states these are softer than the OEM and will provide a smoother shift (that it does).

I have recently purchased an Innova 3120 & 3140 scan tools (but have yet to use them), would either of these be capable of the scan needed?
Almost forgot, I also have an OBDlink SX scan tool.

 

I am unfamiliar with those scan tools, just as long as they can show live data they should work.

 

I'll run them tomorrow afternoon and let you know the results.