Car - WRX STI 2000 RA
Mods - TBE, suspension
Other Known issues - clutch is slipping needs to be replaced.
When I release the clutch very quickly and press the accelerator at the same time, I feel a big knock/kick/ coming from centre-rear of the car. There is a knock sound also.
When I drive it normally, i.e. release the clutch normally, dont accelerate to fast, then there isn't any issue.
Is this something to do with the rear center differential?
What could be the cause and what do you think I need to fix?