tearing up 727s. HELP

[Formula95]

I had the transmission in my roadrunner rebuilt..because when i purchasd the car..it felt weak and eventually started slipping. Well..i had the trans rebuilt by a local individual and addded a 2500 stall. Well the first time i got on the throttle all the way ..right when i let off I heard a clattering noise from the transmission...soon after that the trans started to slip . I pulled the pan and found pieces of what looked snap ring. I then ordered a TCI transmission and a different convertor...the first time i got on it all the way... the transmission made the same noise when i let off..and now the front pump is whining and also leaking...so i gave up on it and parked it for now. The 440 has 400HP at most...Im runnig Type F fluid...a Aux. Cooler and a lokar pressure cable. the flexplate is one of B&Ms units for cast crank 440s, because the convertors i have been using have no weights on them and the 440 is a 73 cast crank engine. I was wanting to to get any and all opinions on this problem.....im puzzled. thanks!

[1972roadrunner]

maybe the aux cooler is clogged and not letting enuff fluid by for when you romp on it? also, is your lokar cable adjusted correctly?

after i rebuilt my 340 for the first time, the tranny was eaten up from the increase in power, and kickdown cable not adjusted properly. had it rebuilt with all racing bands etc and a hemi 5.0 lever, and i have not had a problem since.

[dwc43]

Are you sure your getting the converter in there right. It will break the pump if you dont. And it happened on two tranny's now. Those stall converters are twice as hard to install as a stock one due to closer tolerances on the splines. Plus a non lock up and lock converter wont swap either.