Pioneer Cables 758004 Automatic Transmission Clutch Piston Seal

Automatic Transmission Clutch Piston Seal

Pioneer Cables 758004 is an exact-fit automatic transmission clutch piston seal for forward clutch inner and outer applications. It is built for service work on a wide range of GM rear-wheel-drive vehicles, including Chevrolet C10, GMC C1500, Buick Regal, and Pontiac Firebird applications.

This part cross-references 3947086 for the same application.

Key Features

• Automatic transmission clutch piston seal for forward clutch inner and outer positions
• OE-style replacement from Pioneer Transmission Components
• Exact-fit design for transmission rebuild and repair work
• Compatible with many THM250C, THM350, THM350C, and THM250C/M31 applications where noted
• Part number 758004 for easy identification

Detailed Description

Pioneer Cables 758004 is a transmission sealing component used in forward clutch service on a broad range of classic Chevrolet, GMC, Buick, Oldsmobile, Cadillac, and Pontiac vehicles. It is listed across many 1969-1986 applications, including Chevrolet Camaro, Chevrolet Caprice, GMC Jimmy, Pontiac Grand Prix, and Oldsmobile Cutlass models. Where noted in the fitment data, certain vehicles require specific transmission types such as THM350, THM350C, or THM250C/M31.

As an exact-fit replacement part, this seal supports transmission rebuilds that require accurate sealing at the forward clutch piston. The 758004 part number is also useful when matching service parts against interchange reference 3947086.

Common Repair Uses

• Restoring forward clutch hydraulic sealing during transmission overhaul
• Addressing fluid loss at the clutch piston seal area
• Correcting shift quality issues tied to worn internal seals
• Replacing aged or hardened transmission seal components in GM automatic transmissions

Installation Notes and Tips

Verify the transmission code and application notes before installation, especially on vehicles marked THM350, THM350C, or THM250C/M31 only. Confirm the forward clutch inner and outer seal location against the service manual for the specific transmission being rebuilt. Clean all sealing surfaces thoroughly and inspect related clutch components before assembly.

Quality Assurance

Pioneer Transmission Components are positioned as exact-fit replacement parts for transmission service, giving technicians a direct-fit option for rebuild work. Part number 758004 is supplied for application matching across the listed GM vehicles and transmission families.