Will not up shift

[94Astro_problems]

Transmission was replaced with a remanufactured "M30" (4L60e). And 45,000 miles later- it had no signs of slipping/wearing- one day just would not shift into 2nd gear. Will not manually shift at the column. Took it to shop#1 and was told the vss"buffer" was loose, and it wasn't connecting properly. I have 3 of these "buffers" and when disconnected, the ABS light comes on, and speedo does not work. I can plug in any of the 3 that I have, and light goes off, speedo works fine.

shift solenoids were replaced, fluid filter replaced, half "old" fluid returned with a quart of lucas "no slip syrup" and new fluid top off. (with engine running) vss on the back end of tranny has also been replaced. I took it to shop#2 (150$) and all they told me was, the ecu "brainbox" aka-computer, was controlling the solenoids, and "likely internal issue" and thats it! ran codes: "egr valve" and "torque converter quad controller"

I'm almost positive its electrical! and i'm not burning this one up!

the buffer is a little whit box, although there is a bigger black box near it with a similar size/different connector "chip" not sure if i should try to swap that out with another one?-not even sure what this chip is/does. I'm at a loss...

I've got almost 500$ in fixing this van (new battery, tow to shop, diagnosis, solenoids, filter, vss) and whats eating me alive is I have a 350turbo tranny in a rv with a blown motor! grrr!!!