1997 Chevy Silverado k1500 Newly remanufactured stage 2 built 4L60E Transmission p1870 code

Just installed in my 1997 Chevy
Silverado k1500 5.7L vortec a new
remanufactured 4L60E Stage 2 built
Transmission with following installed
inside the transmission, STAGE 2
UPGRADE
SONNAX 5 PINION PLANETARY GEAR-
SET, SONNAX FWD DRUM BILLET
INPUT, SONNAX SUPERHOLD (OD)
SERVO, SONNAX 3-4 Z-PACK, and
Torque Converter [(HD)BEARING TYPE
1400-1600 STALL]. With a new HEAVY
DUTY HAYDEN TRANS COOLER. I have
only driven it 475 Miles total since it
was installed 4weeks ago. After 125
miles the MIL came on with P1870
TRANSMISSION COMPONENT
SLIPPING HARD SHIFT 1ST-2ND. I had
PCM SHIFT POINTS reset to 0. Then at
387 miles the MIL came on with p1870  
code TRANSMISSION COMPONENT
SLIPPING. I had PCM completely
reprogrammed for the stage 2
Transmission again. Now the same
p1870 code at 475 miles. I know the
company who built the transmission
tested and dyno tested the
transmission before shipping it to me. I
also know that the valve body is
upgraded and the TCC valve is
upgraded. The transmission doesn't
seem to be slipping and seems to shift  
fine to me, I can usually notice anything
out of the ordinary. My question is why
am I getting this code with all the latest
updates and upgraded parts? I know
that the p1870 code can relate to the
Torque converter clutch slipping on
lock up, actually GM doesn't fully lock
up but more of a pulsate, a bad TCC
VALVE SOLENOID,  or leaking TCC
VALVE. Don't see how it could be the
TCC VALVE because it is not a stock
factory valve, but the upgraded part.
Also if it was dyno tested before
shipping, why would it be the Torque
converter clutch slipping? Seems like it
should work properly, however I
understand mechanical failure happens
with no explanation. The transmission
has a 5yr/100,000 Mile warranty, I just
hate the thought of having it pulled and
sent back to have a new one built and
sent back to me 2-4weeks later
resulting in no truck for another 6-8
weeks total.
I would appreciate any advice on what
else might be the culprit. Could it be my
PCM? I just hate the thoughts of having
my mechanic friend pull it back out and
have my truck in his way for several
weeks, and then put it back in when
new one arrives. Not to mention the guy
who owns the company I bought it from
to have to build me another
Transmission if there is nothing wrong
with the one I have now and it be my
PCM that is faulty.
Again any advice and insight is greatly
appreciated.