From the FAQ:
"Replacing the rear axle with a Ford 8.8" (out of a 1995 or newer Explorer), or a Dana 44 (Metric-tonne Commanche (MJ), Towing-package Cherokee (XJ)) are a direct bolt-in once the spring perches are welded into place. Also, some of the newer Toyota axles also have the same wheel-bolt-pattern as a stock YJ, and their width is just about perfect as well."
From another thread:
"87-91 Grand Wagoneers had Dana 44's front and rear with either a 2.72 or 3.31 gear ratio"
I'm starting to look around for a Dana 44 rear to replace my Dana 35. I'm in no hurry. Will look for something in good condition at the right price. Ideally, I'd like to find a TJ Dana 44, but that might be difficult and/or expensive to find.
At this point, I'm just not sure what donor vehicles have suitable Dana 44s. Even worse, if an axle is out of the vehicle, what should I check? Axle width? Gear ratio, of course. Any help?
And for all you Ford 8.8 fans, don't worry, every Explorer on the road is seen as a potential donor vehicle.
Any other vehicles will give you more issues. Old grand wagoneers have 6 lug wheels as do isuzu rodeo/honda passports.
you need to check axle ratio or be prepared to change gears eventually
other options equally as easy as the top 2 are ford explorer 8.8" or 2wd toyota 8" all 5 have 5x4.5" wheel bolt patterns and are nearly identical in width. another advantage of the 8.8" and 8" is that they come stock alot of times with 4.10 axle ratios due to v6 and 4cyl engines they use
The reason there is a lot of info on the 8.8 swap is that there are a ton of them in the junk yard (thanks cash for clunkers). They also have the correct bolt pattern and a useable width so you don't have to buy new wheels or adapters. The rear brakes aren't great, but I would consider it an upgrade over the stock d35 drums. They are also commonly found with gear ratios that you would actually want to use in a YJ that is potentially getting some larger tires.
The easy d44 swap options are very limited as only a few vehicles came with a d44 that matches the width and bolt pattern of the YJ, and those were produced in very limited numbers by comparison to every explorer that rolled off the line. If you find a Cherokee (XJ) d44, go for it. At least buy it if it's cheap and you can easily make some money reselling it. A Waggy or Scout rear axle could be used but would require new wheels or spacer/adapters. The EB 9" is not bad, but still needs wheels or adapters, and you are also getting old drum brakes and a very low pinion .
If you are swapping both axles, get a matched set from whatever you like, but if you are only swapping the rear I think the 8.8 is the best bet w/o breaking the bank.