Low and high fluid levels induce foaming . air compresses , oil does not

I wonder if the pump got damaged some how?

Mine after the rebuild was like this . but it was also three qrts low. And I don't care what people think, it will have air bubbles that get trapped and your fluid level will change after driving the first time. If the pump was damaged then all gears would suffer . I think you got something in a shift solenoid. Or an apply some were .

Could be an issue with the wire harness too. They are easy to damage.

The flare would indicate a load not being applied. Either it engages slow or releases slow. It allows rpm to spike . with wiring it , most the time, works or it don't . it sounds like a mechanical issue . something is restricting the flow before and or after a solenoid is commanded or a band piston . I would think if a one way is damaged you'd have no second or reverse( I think that's his it works, not a trans speicalest .).

works perfect under w.o.t. anything less and it flares on the 3-4 shift. Either it needs programming or i just need to put the stock plate back in.. can you run the stock sep. plate and remove the 1-2 / 2-3 springs since my stock 2010 4r75w plate already has some factory changes? Any one else have any issues with a jmod on a late model 4r75w?

I had 3-4 flare issues (went to neutral and stayed there for a few seconds) with a BOC tune after transmission rebuild. It must have been there before too.

I fixed it by accident after updating SCT X3 firmware and reapplying the same BOC tune. Worked perfectly 100% of time. Not sure if your issue is related.

yeah i dont have a tune currently. wasnt a problem before but all the shifts were softer than i wanted. Does the BOC tune raise line pressure or?

here is no BOC tune. There is no BOC.

blue oval chips tunes or mo's or whomevers

I had some pretty long shifts on my 4r75e 2011 LX even with a tune. Following Lonnie's recommendation, I did a J-mod. Besides drilling out the separator plate, I replaced the stock accumulator springs with hi-performance (softer) ones from Darrin @ BC Automotive. Also replaced the OD spring with a softer one for quicker engagement. The shifts are nice and quick without being harsh (no chirping).

All right so here goes.. problem 1:slipping going into overdrive bad o-ring on the epc. New epc didnt fix it.. led to a new epc which was defective wouldn't seat perfectly but enough slop in the bracket to not notice unless you look from every angle.replaced that and the shifts cleaned up a lot but not perfect. 1-2 was still mushy and 3-od was ehhhhhh with a little slip. new ss1/ss2 and sonnax od pin plus sonnax pressure reg. valve and spring.. presto shifts like a million bucks. thanks for all the help

After seeing this post I decided I`d better check my trans fluid level..I had a trans serv. done about a year ago from a trans shop...
Good thing I checked..It was 16oz`s over filled...Sucked out enough to get it down to level...