d35 8.25 swap

[Geonovast]

Overall changing out a rear axle is a pretty simple thing to do. Changing the speedo gear is pretty easy as well, you just have to find one. Should be plenty of 3.55 speedo gears out there, I believe it was the most common axle ratio in the XJ/MJ.

[Pete M]

he's referring to the little plastic gear in the speedo cable where it goes into the trans. a very simple swap. :thumbsup: and you might not even have to do anything depending on your tire size. when the axle swap is all done, check your speed against a gps and see how accurate your speedometer is.

 

[Incommando]

I was assuming that you had adjustable control arms & trac bar with your 4" lift. If you do not you will need them to go higher. So even if you just bought front top spacers to make your front 4" lift springs equal the SOA rear on stock springs you would have to invest in the other suspensions pieces as well if they are not already in place. I went adjustable when I did my 4" lift. I was able to do the relocation trick to get my front brake lines right for a 4" lift but I don't think they have that much left for a taller lift if the front flexes much.

 

Even with 32's I noted a power deficiency with the factory 3.54's. Depending on your tire size the stock gears may prove unlivable for you.

[mvusse]

To get back to the brakes, I put ZJ Grand Cherokee disc brakes on my 8.25". I had to make the center hole in the brackets and backing plates larger to fit over the larger diameter axle tubes, but aside from that it was a direct bolt in.

 

There are different ways to make the hole larger. I've heard of people using a die grinder or a Dremel. I used a 2,75" hole saw (to act as a "centering pin") inside of a 3" hole saw on a drill press turned to the lowest speed (250rpm) with lots of oil. Took about 30 seconds per bracket.