Originally Posted by kdub
I didn't have to modify my cross member or swap my axles.the 4.10 gearing is not to ( I think you meant low) for the 4.0
Depends on the tires, and what he wants to do with the jeep.
I like the 4.2 with 33" tires and the 4.10, but the 4.0 is a higher revving engine so it could be a bit high.
But I suspect with up to 31" tires it would be fine.