94' 4.0 Auto tranny issue

[Colton - 94 Ranger]

Hey everyone, 1994 4.0 with auto tranny. I recently took it to the mechanic back in early December for a weird random idle, while in the process I had about 10-11mpg, so my mechanic diagnosed and found ATF all up in my vacuum system and found I believe what he said was the vacuum modulator. He replaced all vacuum lines and had to take the exhaust off and replaced the modulator aswell. I got it back and it when i took off, it shifts to second gear smooth then downshifts real quick, then back up. So it goes shift 2, downshift right after, then shift back up. My mechanic took it back and said my kickdown cable was bad and broken. He then ordered the part, and it took 2 weeks of at the shop and he told me the part is near impossible to find, other things happened involving a break-in, and my truck got scratched so that's got to get fixed too. Anyways, do any of you guys know what my problem could be with the shifting? I would like to try myself to solve the issue, but I'm not sure what it could be, that cable seems to be very hard to find. So I'm open to ideas as to what it could be.

 

[rumblecloud]

There was a string here earlier from someone looking for a kick down cable...here:

Kick Down Cable string

It may offer some direction.