Throwback Thursday: What You Should Know Before Modifying Your Rearend

Wow, how time flies. It’s once again time for another Throwback Thursday? Let’s do everything we can to make this a great day. The arrival of the day after Humpday means another week is almost over. For this week’s look back, I thought we would check out an article published in March 2018. Yes, I’m going back a few years, but the information is still relevant.

It was a long time ago when we published this article with help from Moser Engineering, and in it, we discussed how to avoid messing up a perfectly good rearend. The article, Info You Need To Know Before Modifying The Rearend In Your Ride, explains all about being sure you adhere to all of the driveline alignment rules so you don’t have any unwanted vibrations or wear issues. In the article, we spoke with Jeff Anderson at Moser and asked him a few questions about what to consider when getting your rearend in gear to fit wider rims and tires.

narrow rear

Instead of buying new axles, a cost-effective option for fitting bigger tires is to have your original housing chopped down and the axles re-splined. You need to ensure that the axle diameter does not get smaller than the splined area, or else there will be no material on which to cut splines. If the donor rear is wide enough, and the differential is off-center, you may get away with only cutting and re-splining one side.

We started by asking Jeff, what are some considerations when wanting to cut and re-spline axles? “Cut and re-spline is an option that we offer for some that are on a budget and/or trying to use a pair of axles that otherwise would have been thrown away. It does require planning and checking of some basic dimensions to make sure it is possible before sending the axles to us. We always advise calling us with this basic information before sending them in.”

In the original article, Jeff also gets into what you need to consider when cutting a rearend housing. Considerations about pinion angle and spring-perch mounting are very important.

narrow rear

“Narrowing a rearend isn’t difficult if you have some experience and some specialized tools,” Jeff originally stated. “Most importantly is an alignment bar. This is a device that maintains the alignment at four different points in the housing. Basically, it aligns both ends of the housing so they are true with the machined areas in the center for the carrier bearings. It utilizes a straight and solid rod that goes thru all four points to maintain alignment during the tacking and welding process. If all four bearings are not aligned, shortened axle and carrier bearing life is almost guaranteed.”

There is a lot more interesting and what might seem surprising information in the original article, and to learn more, you really need to check out, Info You Need To Know Before Modifying The Rearend In Your Ride. Check back with us often, as we’ll be sure to bring you more great tech you can use.

More Sources

About the author

Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
Read My Articles

Dirt Track Racing delivered to your Inbox Weekly!

Build your own custom newsletter with the content you love from OneDirt, directly to your inbox, absolutely FREE!

Free WordPress Themes
ONEDIRT NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

OneDirt - Dirt Track Racing Magazine

We'll send you the most interesting Street Rod articles, news, car features, and videos every week.

OneDirt - Dirt Track Racing Magazine

ONEDIRT NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

OneDirt - Dirt Track Racing Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...



Hot Rods & Muscle Cars

Diesel Army

Engine Tech

OneDirt - Dirt Track Racing Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • Hot Rods & Muscle Cars
  • Diesel Army
  • Engine Tech

OneDirt - Dirt Track Racing Magazine

Thank you for your subscription.

Thank you for your subscription.

OneDirt - Dirt Track Racing Magazine

Thank you for your subscription.

Thank you for your subscription.

Loading