Join Date: Oct 2010
Location: Texas Hill Country
You can determine gear ratio by rotating the drive shaft (or wheel) and comparing drive shaft to tire rotation. You will need to figure out the math or do a search.
The transfer case should have a round (think it was round) metal tag with NP241 - NP= New Process. I think the tag is on the aft end of the case near the drain plug. If the T-case is the 241, you should have the proper gear ratio in it (the NP241 was used in other applications with different gear ratios, but I wouldn't worry you had the wrong one.)
If it does have a D44 axle (odds are great it is the real deal) it will have the appropriate axles - a D44 axle won't fit into a D30 and vice versa. If you buy this and want go the mod route with lift and larger tires, you will want to replace all of the axles with chrome moly high strength versions anyway.
If a locker doesn't engage, I wouldn't buy it unless you are going immediately with the upgrade route - Dana 60s and/or ARB lockers. A locker problem could be dirt simple to fix or it could be really expensive - usually it's one extreme or the other.
On pavement, engage rear lockers (need to be in 4-low) by pushing locker switch once. Locker light will flash for a few seconds until it actually engages. Make tight turns and feel the locked axle (it's obvious), you might hear a tire chirp. Push the locker switch again to engage the front locker and make the same driving test. You cannot engage the lockers in 4-high or the fronts only without a mod. Pull the switch up to disengage.
Check the steering linkage (tie rod and drag link, ball joints) by having the salesman turn the steering wheel (parked, engine off, ignition switch on to where it unlocks steering wheel) while you look at the linkage. It should be 'tight' with no play.
Like buying any used vehicle, listen for any unusual noises from the engine and drive train. Be sure and do a highway drive at 50+ MPH, shouldn't be any loud whine or vibration or steering wheel wobble.
Oh, one more thing to check - a digit in the VIN will indicate if it left the factory as a Rubicon, do a search for that specific detail.
John - WB5THT
2006 LJ, not stock