Speedmaster®
GM 8.875" 12 Bolt 12P Car 35 Spline 3.07 up TorqueWorm Limited Slip Differential
Product Information
Overview
Specs
| Brand: | Speedmaster |
| Part Number: | PCE204.1039 |
| Part Type: | Differential Carrier |
| Differential Case Design Type: | GM 8.875 in. (12-bolt), passenger car |
| Aftermarket Carrier Style: | Limited slip |
| Cover Bolts: | 12 |
| Axle Shaft Spline Quantity: | 35 |
| Manufacturer of Axle: | GM / Speedmaster |
| Carrier Material: | Steel |
| Carrier Bearing Included: | No |
| Quantity: | Sold individually. |
| Notes: | With use of PCE203.1005 and PCE440.1017 in order to fit on standard cases. |
Description
The GM 8.875" (often rounded to 8.9") 12 Bolt axle is available in passenger car (GM 12P) and truck (GM 12T) rear axle configurations and features an 8.875" ring gear and 35 spline semi floating axle shafts. While both versions of the axle have similar specifications on paper, they do have unique differential carrier housings and most parts, including ring and pinion gears are not interchangeable. Because both axles are commonly referred to as GM 12 Bolt axles, it is important to know which version you have before ordering your parts.
The easiest way to tell them apart is that the passenger car version has a perfectly round differential cover while the truck version has an irregular shape.
Warranty Information
Prop 65 Warning
Installation Guide
Our AI assistant generates a step-by-step guide for this product — covering installation, maintenance, and troubleshooting.
This AI-generated guide is for general reference only and does not constitute official Speedmaster product documentation. Always verify fitment, torque specifications, and safety requirements before installation.