Our Build Process
Much more than just “Welding the diff”
Welding a differential may sound simple, but the quality of the finished carrier depends heavily on what happens before, during and after the welding itself.
At WeldedDiff.com, we use a standardized process to clean, prepare, preheat, TIG weld and inspect every differential carrier we build.
The goal is straightforward: produce a clean, properly prepared welded carrier with strong, consistent welds that permanently lock the differential for drifting and motorsports use.
We are not interested in simply filling the inside of a differential with weld. Preparation, heat control, weld placement, metallurgy and inspection all matter.
This is the page where we layout the whole process in an effort to educate you why our differentials stand the test of time and why you shouldn’t let just anyone weld your diff. Click any of the buttons below to jump around.
Step 1: Initial Inspection
Every carrier begins with a visual inspection before welding.
We look for obvious damage or conditions that could prevent the carrier from being suitable for our process, including:
Cracks
Broken gears
Significant corrosion
Damaged bearing surfaces
Previous modifications (including, but not limited to welding)
Evidence of catastrophic differential failure
Other structural damage
Used differential components will naturally show wear. Normal wear, discoloration and cosmetic imperfections are expected.
What matters is whether the carrier and internal components are structurally suitable for welding and continued motorsports use.
Step 2: Cleaning & Degreasing
Differentials spend their lives submerged in gear oil, which means thorough cleaning is especially important before welding.
Oil, grease, dirt and other contamination can interfere with weld integrity. Making sure the weld is structurally sound is far more important than how “good” it looks.
The carrier is cleaned and degreased to remove as much residual lubricant and contamination as possible from the entire carrier. Special attention is given to the areas that will be welded. Particular attention is paid to the internal gear assembly, carrier windows and the surfaces surrounding the planned weld locations.
This is one of the least glamorous parts of the process, but it is also one of the most important.
Why Cleaning Matters
Welding contaminated metal can contribute to:
Porosity (weld that looks like Swiss cheese)
Poor fusion (lack of penetration into the base material)
Inconsistent welds
Contamination of the weld pool (causing porosity under the surface of the weld)
A clean carrier gives us a much better foundation for the welding process. A dirty carrier will subject the welds to porosity, providing conditions for cracks to start and propagate from.
Step 3: Weld Area Preparation
Once the carrier is clean, the areas that will receive weld are mechanically prepared.
Surface coatings (rare), oxidation, remaining contamination and other material that could interfere with welding are removed from the required areas to expose clean base metal.
The goal is to create clean contact areas between the differential gears and the carrier so the weld is joining prepared metal rather than trying to weld through years of oil residue, oxidation or surface contamination.
The exact preparation varies somewhat depending on the design of the differential carrier.
Step 4: Preheat
Before TIG welding, the carrier and gears are preheated.
Differential carriers contain substantial amounts of metal, which can pull heat away from the weld area very quickly. The specific alloys used in gear making, while being impressively strong, can be incredibly brittle when the wrong conditions are present. Think about a drill for example… drills do not bend. Drills shatter. There’s a tradeoff in metallurgy where (most of the time) the harder the alloy, the more brittle it is. Preheating helps bring the assembly up to a more controlled starting temperature before welding begins.
This helps us manage the temperature difference between the weld area and the surrounding carrier during the welding process.
Our preheating procedure varies depending on the carrier design and materials being welded.
Step 5: TIG Welding
Once preparation and preheating are complete, the differential is TIG welded.
We use TIG welding because it gives us precise control over heat input, weld placement and allows us to use the correct filler material to join dissimilar metals. This is one of the major failure points of processes that use MIG welding.
Rather than relying on one large mass of weld, the objective is to create strong, non-brittle, connections at the specific locations required to lock the internal gears together and secure them to the differential carrier.
Our weld pattern is designed to lock all of the differential gears as a single assembly, without distorting the assembly as it cools.
Depending on the carrier design, this includes welds:
Between adjacent internal gears
Between the gears and the carrier
Around the appropriate perimeter areas of the gear assembly
The exact weld pattern varies by differential design.
Why TIG?
TIG welding gives the operator a high degree of control over:
Heat input: Precise control is required to ensure that the part is not overheated or welded too cold (causing lack of fusion)
Arc placement: We aren’t adding anymore material to the rotating assembly than is required to do the job and to keep it balanced.
Filler addition: We use the correct filler alloy to join the dissimilar materials that diffs consist of. Using any old filler will cause cracks as the weldment cools.
Weld size: Weld bead size is determined by the size of the joint, not the settings on the machine.
Weld bead placement: We’re welding only where necessary. Nothing more, or less, than what is required.
Work cleanliness: Zero weld spatter, BBs or left over material will be left in your diff to get caught in the ring and pinion.
For the relatively confined areas inside a differential carrier, that control is valuable.
Step 6: Welding Sequence
Heat management does not stop once welding begins.
The carrier contains multiple gears and several weld locations, so the welding sequence is managed to avoid concentrating unnecessary heat in one area of the assembly.
Rather than treating the carrier as one continuous weld, the different sections are tacked and then welded in a controlled and even sequence. The sequence is similar to how OEMs manage torque sequences on critical components, like head studs/bolts.
This allows heat to be distributed more evenly throughout the assembly while the required connections are completed.
Step 7: Post-weld Cooling
After welding is complete, the carrier is allowed to cool in a controlled manner.
We do not want to unnecessarily shock a hot carrier immediately after welding.
The objective is to allow the assembly to return toward ambient temperature gradually while minimizing abrupt temperature changes. This prevents the metal from becoming unnecessarily brittle, or even crack as it cools.
Step 8: Final Inspection
Every completed carrier receives a post-weld inspection.
We examine the completed assembly for:
Complete weld coverage at the intended locations
Visible weld defects
Missed or incomplete weld areas
Cracking
Damage caused during preparation or welding
Overall condition of the carrier
Only after the carrier passes this inspection is it considered complete.
A Repeatable Process
The biggest difference between WeldedDiff.com and having someone casually weld a differential is not simply the welding machine being used.
It is the process surrounding the weld as well as the weld itself.
Every carrier goes through the same basic stages:
Inspect → Clean → Prepare → Preheat → TIG Weld → Cool → Clean → Inspect
That repeatability allows us to treat welded differential carriers like a standardized motorsports product rather than a one-off modification.
Built for Drift and Motorsports Use
Our welded differential carriers are intended for vehicles where permanent rear-wheel lock is desired, particularly drift and motorsports applications.
A welded differential changes the way a vehicle behaves. Both axle outputs remain mechanically locked together, which can create tire scrub, chirping and additional driveline loading during tight turns and normal road driving. For dedicated or primarily drift-focused vehicles, however, that permanent lock provides the consistent rear-wheel behavior many drivers are looking for.
Professionally Prepared. TIG Welded. Inspected.
Every WeldedDiff.com carrier is built around the same goal:
Produce a properly prepared, consistently welded carrier that is ready to be put to work.