Looking for some 4L80e pressure help. Recently installed an HD2 shift kit on a junkyard trans of unknown history. Drilled orifices in separator plate to 100 thou and no pressure relief mod. I drove the car for a few days and all was fine. As I started upping the boost, it began to slip at the top of first gear. First a delayed shift, now it won't shift at all at wot. Now it feels like it's slipping everywhere. Pressures are as follows:

Idle only, warm fluid
Park: 90lbs
R: 125
N, D, 3: 90
2: 110
1: 90

Doing a quick rev to 3k rpm, warm fluid, car on lift, wheels allowed to turn
Park: 180
R: 270
N, D, 3, 2, 1: All 180

With large circular electrical connector disconnected:
P, D: 180
R: 300

No slip codes.

Car has a 3600 stall from a well known supplier. When I try to drive it, it just rolls along and you cannot feel any shifts at all with light throttle now (I could barely feel them before). If I lock the TCC and roll along light throttle, each shift can be felt solidly. This had me thinking perhaps a converter issue? But I think that's unlikely.

All of the above to me means this trans is just tired and needs to be gone through, especially considering it only started slipping after adding more power. Is there anything I could have done wrong in the HD2 install to cause these symptoms?

Thanks,
Adam

 

Also of note, car drove fine with less boost before the addition of the HD2, although the shifts were never particularly firm.

 

I'm guessing the dipstick was never properly marked?
I'd suspect there is a low fluid condition

Which now has probably caused the need for a rebuild

 

This is a possibility. The dipstick in it was not reading correctly.