bottom line- the TCC duty cycles on/off and slips constantly, by design. the net effect is like riding the clutch in a stick shift car. this fills the trans with tiny particles down to 20-25 micron size. the factory filter only catches down to 60 micron particles. the smaller particles eventually get past the filter, and clog up the electronic solenoids and valve body.
you can either pull the side cover and change the solenoids, a major PITA job, and hope for the best....cuz sometimes even that doesn't fix it, if there's a lot of clutch dust in the trans- it will hang up again short time later.
or, you can disable the TCC altogether. and just drive it like an old style automatic trans with no TCC. your choice. your money and time. take your pick. even if you fix it perfectly with an NOS GM trans, eventually it's going to happen again. guaranteed Vegas casino house odds on that.
if you put a pound of clutch dust into a trans with the fluid, you have to take a pound of clutch dust out. if you take only 1/2 pound out, the rest of that dust will wreak havoc in the valve body. common sense.
these trans are seriously under-filtered, they need an aftermarket inline filter to catch all that material- even then some may get into that delicate valve body/solenoids and clog it up.
