Timing gears on the 4.0 and 4.2 are identical. Do not get a stock/OEM set, get a triple roller steel set if you can, they can be found on summitracing.com or similar places.... If that gear hitting the floor was enough for it to break, it's a good thing you dropped it, lol. Also, those seals are very common.... Just be very careful in removal and installation, if you scratch the surface the seal sits on, it will always leak unless you use sillycone.