TOPIC:

found this

Tamiya 54424 3x3mm Bushings - for Ball Differential (12pcs)
By replacing diff balls with these bushings the differential effect can be disabled to give the same effect as a spool diff. If the diff receives a strong enough shock, in the event of a crash, the bushings will allow the diff to slip, providing a slipper clutch effect.

You can get these at Banzaihobby and of course other suppliers


Specs and Features
Ball Diff Bushing x12
Compatible with cars with ball diffs that use 3mm diff balls.

sounds interresting, anybody who tried this?

Heard of it - looks like a good approach. Better than the (circular) rubber "paddings" for locking...
Thanks for the part number! May have a go at it.