Front axle has a separate fill and drain plug. Rear axle has a rubber fill plug only. You have to pull the rear cover to completely drain the axle for a fluid change. The US spec Liberty CRD uses the Chrysler corporate 8.25" rear axle. I purchased a PML aluminum diff cover for the rear. The PML cover has a threaded drain plug and a threaded fill plug at the correct height. I installed the cover at the first fluid change and should never have to pull the cover again. After installation of the PML cover, fill with gear oil until it runs out the fill hole........just like the factory cover. Axle oil capacity increase by .75 qts with the PML cover. In my opinion, the PML cover is the best aftermarket cover, but it is the most expensive. I paid $195 shipped.
http://www.yourcovers.com/