Hi got told by my diff shop when I got 4:1:1 put into the car I had play in my drive shafts as my tailshsft has some play in it and I can feel it clunk under acceleration and instead of doing driveshafts I was gunna do my universals joints because I know having worn unis thatll also cuz tailshaft play and backlash as my old mans forbe had this issue..and also the shop might just be trying to grt bit extra cash outer me..so im gunna do unis first see if it takes up the play..ive done em once before years ago but need a freshen up just to make sure I remember correctly before I start pulling things apart..anyone got step by step info? Cheers

Is this vehicle a sedan or wagon or Ute?

Have you checked the Rubber Centre joint on the Tailshaft? ( if it is a sedan )
They are a problem on BA's and can be responsible for the noise.

All good my diff 4:1:1 was outrr calibration for the gearbox had to flash tune it cheers