Sonnax Performance 4L80E 4L85E Input Shaft 300M Heavy Duty handles up to 1000HP

Sonnax Performance Input Shaft 300M

Part No. 34670-01

Fits 1991-On 4L80E & 4L85E Models

Input shaft failure is a common issue in high-performance and heavy-duty GM 4L80-E and 4L85-E transmissions. The Sonnax 34670-01 input shaft is engineered from ultra-strong 300M alloy steel and undergoes proprietary heat treatment and post-processing for unmatched durability and value.

The outer diameter (O.D.) carrier spline—where shafts typically fail—is significantly reinforced. By eliminating the OE undercut and adding extra spline material at the major diameter, this design fills the root gap of the internal O.D. carrier spline, dramatically improving strength.

Recommended for applications up to 1,000HP.

• Advanced torsional design with spline and cross-hole refinements
• Hobbed O.D. carrier spline eliminates deep undercut failure points
• Extra spline material enhances structural integrity

Specs

• Material: 300M alloy steel
• Installation: Requires experienced technician
• Transmission removal: Yes