It was in the early release of the GTB and sorry cant remember what motor it was... I am used to gear diff in 8th scale and Durango and they dont loosen off and change like ball diffs..harder to change setting as you need to change oil but havent bothered with SC10 and still has grease in it as RTR I got and stll feels super smooth and may have a play with some oils but dont know if it would make a marked difference as goes fine.