700r4 3-4 clutchpack

just rebuilt tranny, replaced everything.
The 3-4 clutchpack almost instantly burned the clutches out.
We are thinking the new clutches were thicker than the old ones and as such we should NOT have used the super thick last steel, (we think total thickness of pack was too much) and burned it out?
Is there any specific list of things that might cause just the 3-4 to burn out almost instantly?

The list of things that can and will go wrong is really long,,,,the clearance of the clutch pack is not really fussy,,,,as long as there is some clearance.....IF you put it together properly,,,input drum is a bear to install all seals,,,,pressure regulator problems,,,throttle valve problems.....If a control kit ,, Superior,,,Transgo jr ,,and all updates to repair engineering faults,,,,are not done,,,this thing will not last,,,,Don't want to make it sound impossible to fix but most people think new parts solves all the problems,,these are a good to great transmission once you correct all the engineering issues...In your case,,it can be as simple as the gaskets between the seperator plate are not centered and blocking the feed holes to the clutch pack,,,which would have been corrected if feed holes are drilled to aftermarket specs.........am I on a roll,,or what????? good luck

I think you may have helped solve our issue. We were told the tranny was a 1987 though it is a 1985, so some of the gaskets were different, we assumed before that this was an "upgrade" or "fix." We have it back together and are putting back in truck today. Thank you very much.

1985???? was there a black metal retainer over the front pump seal????? early 700s,,,drain back hole in pump is partially blocked by pump seal,,,if not enlarged,,or retainer clip installed,,,nice hot days,,,will blow front pump seal out of transmission,,,,if having problems with up shift,,,,,return springs will have to be installed in throttle valve plunger