GM TH350 Billet CNC Full Manual Valve Body Spragless Upgrade Kit w/ Transbrake

Take your TH350 beyond its limits with our all-new Spragless Upgrade Kit, a complete performance conversion that eliminates the transmissions weakest link and unleashes its true power potential.

Brand:	Speedmaster
Part Number:	PCE634.1013.01
Part Type:	Automatic Transmission Valve Body
Valve Body Style:	Full Manual
Manual Valve Included:	No
Modular Plug Included:	Yes
Trans-Brake Included:	Yes
Trans-Brake Provisions:	Yes
Shift Pattern:	Reverse (P-R-N-1-2-3)
Valve Body Material:	Billet Aluminum
Quantity:	Sold Individually

This kit combines a Billet CNC Full Manual Reverse-Pattern Valve Body with Integrated Transbrake and a Spragless Intermediate Gear System that replaces the fragile factory sprag assembly.

By removing the one-way clutch and converting the drum to a fully mechanical drive, this system dramatically increases strength, torque capacity, and reliability under extreme racing conditions.

Build your TH350 for endless power with this next-generation design.

Key Features & Benefits

• Spragless Intermediate Drive – Replaces the factory one-way sprag with a solid mechanical gear for unmatched durability.
• Eliminates the TH350’s Weakest Link – No more sprag flipping, cracking, or catastrophic failure.
• Adds 1000+ HP Capability – Removes the torque limitation of the OEM design, allowing your build to reach its true potential.
• Billet CNC Valve Body – Precision-machined for optimized oil flow, instant clutch response, and superior hydraulic control.
• Full Manual Operation – Complete driver control with no automatic shifts.
• Reverse Pattern (P–R–N–1–2–3) – Safer and faster for race use.
• Integrated Transbrake – Instant line-lock for hard, consistent launches.
• Race-Proven Engineering – Designed for high-horsepower drag applications and transbrake launches.

How It Works
 

The factory TH350 uses a sprag (one-way clutch) that allows the intermediate drum to freewheel in 1st gear and lock in 2nd.

At high RPM or under extreme shock loads, that sprag often fails catastrophically, limiting the gearbox to moderate power levels.

This kit’s spragless gear replaces that assembly entirely — locking the drum solid and transferring torque directly, with no moving elements to fail.

The manual valve body is specifically designed to manage hydraulic flow for a spragless setup, ensuring smooth gear changes without bind or overlap.

Summary
The TH350 is a proven transmission — now it’s limitless.
Our Spragless Upgrade Kit removes the transmission’s greatest weakness, giving you the strength, control, and confidence to push your build as far as it can go.
Spragless. Limitless. Built for Power.