New servo chattering

[dobber]

I've fitted a new servo to replace my very old but reliable futaba 3003. Got a Savox servo but it chatters a bit and when testing it seems to get interference. When full throttle and turning it will either put the wheels straight or worse go the opposite way. Should I rested the receiver (got a code system with blue rx) this tx and rx worked perfectly before putting in the Savox. Any thoughts as I may have to swap it back over before tomorrow evenings racing.
Ta muchly!