Axle Trusses, Differential Armor, & Stud Eliminators
So you’ve got a 4x4 Toyota finally and want to upgrade the axles. Most people focus on the internals (shafts, gears, etc.) and while those are important, the exterior often gets neglected until it’s too late. These upgrades are mostly preventative—doing them before things break can save you money and downtime.
1) Trussing the axle housing
The first and most beneficial upgrade is trussing your axle housing. A good truss helps prevent axle tube warpage/bending if done correctly. There are a ton of different options out there and most are adequate.
If you are linking your suspension, a truss is essential because the upper links mount to it. Regardless of what brand you choose (or if you fab your own), I recommend at least 1/4" thick steel.
Welding tips (avoid warping the housing)
Care must be taken when welding to the axle—too much heat can warp the housing. General rule: preheat everything and weld only an inch or two at a time, jumping around to various spots. Also make sure your weld surfaces are clean so you get proper penetration.
- Preheat to reduce heat shock and help control warping
- Stitch weld small sections and move around
- Clean metal = better welds
- Let it cool naturally (don’t quench)
2) Differential armor
The second upgrade is differential armor. This is typically a 1/4" piece of steel that welds over the differential and takes the abuse from rocks before your third member does. There are several brands and styles, but they all serve the same purpose: protection.
3) Differential stud eliminator kit
The third upgrade I recommend is a differential stud eliminator kit. This replaces the studs that bolt the third member into the housing with bolts from the inside. Stock studs are known to pull out/strip. By using a bolt from the inside, it prevents the studs from pulling through the threads under load. Most people (myself included) also upgrade to a larger size than stock for extra clamping strength.
More detailed references
More detailed information on these upgrades can be found in the Toyota bible (also linked in the Resources section of the main site).
Final thoughts
I’ve done all these mods to my wheeler and haven’t had an issue with any of them since. Highly recommend them as preventative damage control. Feel free to contact me with any questions.