This is taken from
M.O.R.E.
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Are you having trouble with the stock Dana 35 rear axle in your Jeep® XJ Cherokee, or YJ Wrangler? If you have installed tires larger then stock, chances are that you are. We have found the answer, and it is a very simple swap. The Ford 8.8 rear axle assembly from a Explorer is super heavy duty, and is very simple to install.
It's features are as follows: Same lug nut bolt pattern. Disc brakes (95 & newer). 31 spline axle shafts. 8.8" diameter ring gear (D35 is 7.5"). 120% stronger then D35. Only 20 pounds more then D35. Trac-loc differential stock (woppie-do, I know, who cares!). 3-1/4" diameter tubes (strong!).
You are required to find the complete rear axle assembly from a 95 or newer Ford Explorer, from a salvage yard. Then, remove (torch) the Ford mounts (spring, & anti-sway bar). You may also need to change the gear ratio as most Explorers have 3:73. The installation kit that we sell gives you the following: New, weld-on anti-wrap spring mounts, weld on shock mounts, U-bolts and U-bolt plates.
The width is almost the same. It is 5/8" per side narrower then the D35. This is a very minor draw back, and will work if you have wheels with less back-space then stock. If you have stock wheel back-spacing, then we have hub-centric wheel spacers available. We also have the correct cables for the emergency brake available as a kit, that are a direct bolt on, and super high quality. No cutting or custom fitting.
Note: The Ford 8.8 is not compatible with anti-lock brake equipped Jeep® vehicles!
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Depending on what gear ratio you'll need, I have a 3.73 Trac-Loc 8.8 Explorer disc brake rear for sale. I'll also be picking up a 3.73 open disk brake rear this weekend. Shoot me an email or PM if interested.
The 8.8 into an XJ looks to be one of the easier swaps.

MORE's kit below has new leaf spring perches and shock mounts.