The NV241J from a JK doesnt have a speedo option. It also comes in 2.72 or 4.0/1 low
NV241OR 03-06 Rubicons has a speedo and comes in 4.0/1 low.
241C in a chevy has a slightly different bolt pattern is a 2.72/1 low
(Early models were right drop)
241D same 2.72/1 low & has the chrysler bolt pattern like the Jeeps.
(some came as right drop) (after 98 possible no speedo option)
EDIT:
You can't use the JK 241 in a TJ/YJ series that needs a speedo. UNLESS you give the guys @ ORO a call and use their speedometer retrofit that gives you an external speedo on the JK (They use it for their Airock setups)