V8 disco rattle

my disco v8 auto has developed a rattle like a big end going?.The engine is quiet when cold ,but rattles when hot and under load.If you put it into gear with the brake on the rattle increases. At around 50 mph this rattle disappears and it runs ok.It has recently had a new middle and end silencer box so the rattle should not be this,and a big end would have gone by now.Has anybody any ideas on this please.

cam followers possibly

ret.h.
This is a 95 disco,will listen to the cam followers. butit has been suggested that the torque converter is failing? With all the auto boxes I have driven have never heard a rattle like this before,thought it was big /small end, but these do not go away as the revs increase.Could the torque converter rattle ?

If the rattle going away coincides with the torque converter lock-up speed, then it could possibly be the TC or 'A N Other' transmission component.

Peter