Yeah, sometimes diffs can click, but still look ok (for a while). Could be worth checking your wheel hexes as well, because they can round out and make it look like you have a diff problem.
Does yours have the rear diff spool? (Locks the rear diff)
I had that kit in one of my old Maxx's, and I was constantly snapping off the screws. And it reacted the same way you described. Make sure one of those four little screws isnt sheared off.
Losi 8T 1.0, Savage Flux - XL style, LST XXL, Muggy, 3.3 E-Revo Conversion and sitting outside 425hp, 831 Tq Dodge Ram Turbo Diesel. It SMOKES