Jeeps has used many differentials throughout the decades; most were, and still are Dana's - but they used Timken, Chrysler, Ford, and Spicer (AMC) as well. We'll stick to the basics here ~
CJ series Jeeps started with a narrow track Dana 30 in the front and an AMC 20 in the back and went to a wide track pair in 1984. In 1986 a Dana 44 was a rear end option on the CJ7 but was also used on earlier CJ models.
YJ's continued on with the Dana 30 front axle, but it is not the same as a CJ Dana 30. The rear end became a Dana 35. (Canada used a Dana 44 in some Jeeps)
TJ's also maintained the front Dana 30 but again it is not the same as the CJ or YJ. The Dana 35 also continued on and has the same internals as a YJ but a different external as Jeep switched to coil springs. A dana 44 was an option throughout the TJ series and was stock in the rear and the front in the 2003 and up Rubicon models.
JK's continued to use the Dana 30 in the front, but again it's different from the rest. All JK's have a Dana 44 in the rear and all Rubicon's have a Dana 44 up front as well.
XJ's also used the Dana 30 up front and a 35 in the rear, but also used a Chrysler 8.25 in the rear as well as the Dana 44 in early models.
The Dana 30 was also used in many Grand Cherokees, Liberty's, and more. There are many versions of the 30, some parts are common throughout, some change by year/model. All YJ's, and XJ's/ MJ's through 1991 utilized a vacuum disconnect that is prone to failure.
Like the Dana 30, the Dana 35 has many variations. It was also used on the Grand Cherokee, Commander, Patriot, and many more. From 1990-2006 the Dana 35 used a "C clip" to hold the axle shafts in place, a big inconvenience for trail fixes!
The 44 came stock in many Jeeps such as the Grand Cherokees, SJ's, MJ's, J series, Military Jeeps and more. The Dana 44 is strong axle with many upgrades available, a great choice for the off road community.
Semi Floater vs Full Floater Axles
On a semi floater the wheel bolts directly to a flange formed at the end of the axle shaft. A single bearing supports the outer end of the shaft and is located just inside the housing ends. Therefore, the axle shaft itself has 2 forces acting on it at all times. It has the weight of the vehicle with payload pushing down on it , and the force of the engine twisting on it.
Full floaters use an axle housing with a spindle formed at the end of the axle tubes. The wheel is bolted to a separate hub which spins on 2 opposed tapered roller bearings. Since the weight of the vehicle is supported by the spindle on the housing and not the axle shaft, the shaft is only subjected to twisting forces from the engine.