The West Coast Fiero Custom Axles, specifically the 4T60-E, 4T65-E, and 4T65-EHD models, are designed to adapt Fiero spindles to the automatic transmissions manufactured by General Motors. This adaptation is crucial for ensuring compatibility and seamless operation between these components.

The 440 and 460 transmissions, which are part of this setup, have a unique feature. They can come equipped with either a 34-spline or a 36-spline driver’s side transmission output shaft. The term “spline” refers to the ridges or teeth on a drive shaft that mesh with grooves in a mating piece. It’s important to note that these two types of splines are not interchangeable, which means you will need to count the splines on your specific transmission. This information is necessary for us to send you the correct inboard joint, which is the component that connects the drive shaft to the transmission.

The axles themselves are built to be heavy-duty, capable of withstanding high levels of stress and strain. They are made of 1045 shafting material, a medium carbon steel known for its strength and impact resistance. The splines on these axles are not just cut into the material; they are rolled. Rolling is a process that improves the strength and durability of the splines by compressing and hardening the material. This makes the axles more robust and reliable, ensuring they can handle the demands of high-performance driving.