rear disc from grand cherokee on a 8 3/4

No, the only reason I mentioned the axles is that that was one of the reasons we decided to just put the set up on the 8 1/4 instead of trying to install them on the 8 3/4. I couldn't afford to buy axles right now.
The problem was the rotor would not line up with the caliper on the 8 3/4 without either making some sort of spacer to move the rotor out away from the axle hub of have longer axles made.