Every engine swap needs a driveshaft. Your factory shaft will not carry over once the transmission changes, so it is a required line item rather than an upgrade.
The question that follows is always the same: steel or aluminum, and why does the aluminum cost more when aluminum is the lighter metal? The answer is not what most people expect.
Watch the comparison
The short answer
The aluminum shaft is the stronger of the two, and it is also lighter. It costs more because it is a bigger tube with a thicker wall, not because aluminum is a premium material.
| Steel | Aluminum | |
|---|---|---|
| Tube diameter | 3 inch | 3.5 inch |
| Wall | Standard | Thick wall |
| U-joints | 1310 / 1350 | 1350 |
| Ends | Steel | Forged aluminum (Sonnax) |
| Rotating mass | Higher | Lower |
Why the aluminum holds more power
Two things: larger diameter and thicker wall. A 3.5 inch tube resists torsional load better than a 3 inch tube, and the thicker wall is what carries sustained abuse rather than a single hard hit.
Building the steel shaft at 3.5 inch would add a significant amount of weight, which defeats the point. So the steel stays at 3 inch, which is entirely capable, and the aluminum takes the larger diameter.
The thin-wall warning
If you are shopping around and find an aluminum shaft priced below a steel shaft, stop and ask one question: what is the wall thickness of the tubing?
Cheap aluminum shafts are thin wall. This is the same reason domestic owners replace their factory driveshafts even though the factory unit is already a big 3.5 or 4 inch tube — diameter alone is not strength. Thin wall does not have the material to sustain continuous abuse or the torque levels a swapped car sends down the drivetrain.
Large diameter plus thin wall is a shaft that looks the part and fails anyway.
Where driveshafts actually fail
Watch failure footage online and the common thread is not the u-joint. It is the weld. The weld at the tube shears, the tube comes loose, and the rest follows.
ASE has yet to have a shaft fail at a u-joint or at a weld.
On u-joints specifically, only Neapco and Spicer branded components are used — no knock-off or inferior replacements on any shaft, steel or aluminum. Aluminum shafts use forged aluminum ends from Sonnax.
The part people underestimate: rotating mass
The weight difference between the two shafts is not enormous — it is not a ten pound swing. But rotating mass is not the same as static weight.
Anywhere you remove rotating or reciprocating weight from the drivetrain — crankshaft, flywheel, clutch, wheels, brake components, driveshaft — you get a response improvement out of proportion to the pounds involved.
On a driveshaft, that shows up as on-and-off pedal response and transient response between shifts. In a racing or drifting environment the difference is immediately noticeable. For a nominal price difference, it is the upgrade worth taking.
So which one?
Aluminum if the budget allows. More torque capacity, less rotating mass, better response.
Steel if it does not. The steel shaft will complete your swap properly and is not a compromise on quality — same u-joint brands, same build standard, same weld quality. It is simply a smaller tube and more rotating weight.
Custom shafts
If you do not see your application listed, it can still be built. To quote one, send:
- The measurement from the flange to the seal portion on your vehicle
- Which transmission you are running
- Which differential is in the back, and whether you need an adapter to go with it
Plenty of channels cover how to measure for a driveshaft correctly — get that number right and the rest is straightforward.
Shafts have been built for Volvo, Chevrolet and Ford applications along with the usual Toyota and JZ combinations, plus a number of genuinely odd ones. Custom applications do not cost meaningfully more than the listed shafts unless the change is significant or the transmission yoke is completely different. A shaft assembly is a shaft assembly, and it is not marked up for being unusual.
Build time
Every shaft is made to order, even the listed applications where the measurements are already known. Typical turnaround is three to five days and out the door.
A note on sourcing
Driveshafts are not machined in house. After a long search ASE settled on a single supplier and builder, and they have supplied every shaft since — roughly since 2018. That relationship is why the failure record is what it is.
Shop driveshafts
Direct-fit shafts are listed for 350Z, SC300, IS300, GS300, 240SX S13, 240SX S14 LSx, G35, Supra MKIV and IS300 with UZ series.
Running a Toyota or BMW differential flange? You may also need a Toyota/Lexus to 1310/1350 adapter or a BMW to 1310/1350 adapter.