Upgrading axles versus upgrading diffs?

[danieldean]

I have a reasonably stock 1998 TJ 2.4L that has a 4 inch lift, and the 29inch tires that I got with it feel like I'm disgracing it, so I've been looking at upgrading.

Everything is on a budget, but I'm not trying to make stupid mistakes and cut corners that could come back to bite me, so I've purchased a set of new wheels, upgrading to 33s. I know I'm going to have to upgrade the diffs to 5.13s because the 4cyl will just drag, and I'm looking into the upgrade I need for my rear axle.

I know Dana 35s are a little of a guessing game, so I was looking to switch them to chromoloy which would be stronger than stock 44s. I was reading the description from extremeterrain's page for a kit, which said,

"If your Jeep is sluggish with bigger tires, then this rear axle kit is a cost effective way to solve that problem without upgrading the differential. "

I haven't seen anything about stronger axles improving sluggishness. Is this true? and how does that work?

Could I just upgrade the axles with this ~$350 kit and install them myself instead of buying ~$500 5.13s and spending ~>$1,000 to get them installed?

 

[Mr. Bills]

No, you will need to gear appropriately for the size tires you choose. Stronger axle shafts alone won't address the "sluggishness" you describe.

Also, if you have a Dana 35 rear axle the appropriate upgraded axle shafts are 1541H rather than 4140 chromoly. The simple explanation why is that 1541H is stronger than stock with the appropriate surface hardening for the bearings which ride directly on the axle shafts in the Dana 35.

You can Google "Dana 35 1541H vs. chromoly" and in less than ten minutes learn more than you ever wanted to know, but this photo illustrates the problem: