This may have been covered before but for the life of me I can't find a thread on it any where.
Is there a difference between the Dana 35 housings for ABS and non ABS in a 1997 and newer XJ?
The D35 used with ABS in the XJ wasn't a RWAL variation (I think,) where the sensor and tone ring were located in the housing (sensor) and behind the ring gear (tone ring.) However, the ABS parts can be left in place when installed in a vehicle that doesn't have ABS.
Else, the tone rings and sensors are out at the wheel ends of the shafts - the tone ring is pressed onto the shaft, and the sensor is mounted to the backing plate. Again, these may be used in a vehicle without ABS without incident.
The Chrysler 8.25 under the XJ and MJ
never came with ABS, although there are ABS variations of the axle found under various Dodge light trucks (like the Dakota.)
The Dana 35 used after 1993 or so had roughly even odds of being ABS or no - no fixed rule.
If you have ABS, you have the D35. If you do
not have ABS, you've got a fifry-fifty shot at which axle - look at the cover to differentiate. The cover on the D35 is shaped like an oval, while the C8.25 will have a flat bottom on the housing and has a roundish or a hexagonal cover.
The presence of a "pop-in" rubber plug isn't a reliable indicator, either. Whichever axle you have, if you have the pop-in plug, I'd suggest either getting plugs by the handful (keep some around - they harden and crack after a while,) or get an earlier cover (both axles have been around for a bit) that takes a standard threaded pipe plug, and get a brass plug to put in. Should be 3/8" NPT, and you can get them at the hardware store for a couple of bucks.