turbo 400 trany brake dont hold

[chevyart]

have 67 nove with a 540 horse sbc engine and every so often(when tranny gets hot if i have tranny brake on a little too long)) the car pulls through the tranny brake and i red light. tranny is a little old. sonenoid is fairly new. any idea why this happens? i have a tranny cooler that is cooled by a fan. this has happened a few times over the past year thanks art PS tranny is a turbo 400 with a 3200 -3600 stall converter

[kwkracing]

Sounds like its ready for a rebuild. low or reverse seals are weak and one is overpowering the other when you old it a too long

[chevyart]

thanks kwk you are more than right when you say its time for a rebuild art