1486 MCV problems after rebuild?

We had a guy replace the MCV body with a completely different rebuilt one along with a new mcv pump, new gaskets o rings everything, all new. we replaced it because we were not getting any oil
to the oil cooler in the front of the 1486. everything else worked fine, but that. after the new installation, we started tractor and the oil light came on, the mcv primed its self up right away, but the oil
light remained on. We had great power steering, but thats all. the clutch assist barely works, the brakes barely work, and the ta is stuck in the low side and will not shift up to direct drive. The guy did
replace the little plastic sump check valve thing or what ever with a little steel cylinder thing that fit in their, I'm not sure if it came in a kit or if its a piece of cut off steel rod or what. I didn't know if
that might have anything to do with our problem. When i said the clutch assist barely works, i mean that you can push it in, but it goes down very very slow, like the flow rate is really slow, same
with the brakes, you have to push them in hard and after 6 seconds they will finally provide braking. ta on the other hand, its staying stuck in low. the guy did replace that little plastic sump piece in
the bottom right corner, with a piece of steel i believe he cut off of a rod, i can't remember. we also did the little supercharge system upgrade during mcv rebuild were the brakes are lubricated from
the back pump instead of the mcv pump. what are everyones thoughts?

The guy doing this will fix it, he knows exactly how to but id like to know myself what the problem could be too.

That little piece of plastic is the check valve for steering if the engine is not running.It holds the oil in the system when not running. I don't know of any fix that would let you change the pump oiling the brakes. Sounds like BS to me. Did you check to see if the lines might be plugged to the oil cooler first? Or the cooler itself is plugged?

[that steel chunk is a roller bearing and you install it to test the ta if i thinking right if it in there that why it not working