Hard Parts

TH400 Early-4L80E Case Saver Retainer | Sonnax

TH400 (All Years) 4L80E (1991-1998) Case Saver Retainer Sonnax Part Number: 34762-10 Sonnax case saver retainer 34762-10 for the GM TH400 and '98-earlier 4L80-E is the only intermediate clutch retaining ring case saver that allows the intermediate band...

TH400 Stator Support Shaft | Sonnax

TH400 Stator Support Shaft Sonnax Part Number: 34910S-01 Sonnax GM TH400 stator support shaft 34910S-01 is a heavy-duty upgrade with improved material and design features for enhanced durability. The high-strength shaft is made from heat-treated...

TH400 Shift Lever Kit | Sonnax

TH400 Shift Lever Kit Sonnax Part Number: 38512-01K Sonnax shift lever kit 38512-01K uses an O-ring on the shaft to prevent leakage from GM TH400 cases. Built with sturdy, solid steel construction, the lever will work with all the common competition...

TH400 Smart-Tech® Drum Module | Sonnax | Racing Applications

TH400 Smart-Tech® Drum Module FOR RACING APPLICATIONS THAT DO NOT USE FRONT BAND AND RUN A 1'' MAIN SHAFT Sonnax Part Number: 34555-01K Sonnax Smart-Tech drum module 34555-01K for racing GM TH400 transmissions improves on-track performance and...

TH400 4L80E Planet Pinion Pin | Sonnax | 4-Pack

TH400 4L80E 4L85E Output & Reaction Planet Pinion Pin Sonnax Part Number: 34875-01   Pack of...

Powerglide TH400 High RPM Checkball Capsule | Sonnax | 5-Pack

TH400 Powerglide High RPM Checkball Capsule Sonnax Part Number: 57510-01 Sonnax high RPM checkball capsule 57510-01 is specially calibrated to prevent pressure drops in high RPM GM TH400 and Powerglide racing applications. Testing has shown that OE...

TH400 4L80E 4L85E HD Main Shaft | Sonnax

TH400 4L80E 4L85E Heavy Duty Main Shaft Sonnax Part Number: 34672-01 Main shaft failure is a common problem in performance and heavy duty GM TH400, 4L80-E and 4L85-E units. Sonnax heavy duty main shaft 34672-01 is manufactured from high strength 300M...

TH400 HD Input Shaft | Sonnax | WITHOUT Turbine Support Bushing in Converter Style

TH400 Extreme Duty Input Shaft  FOR USE WITHOUT INTERNAL TURBINE SUPPORT BUSHING IN CONVERTER Sonnax Part Number: 30280-01 Input shaft failure is a common problem in performance GM TH400 transmissions running with added horsepower. OE and...

TH400 HD Input Shaft | Sonnax | Turbine Support Bushing in Converter Style

TH400 Extreme Duty Input Shaft  FOR USE WITH TURBINE SUPPORT BUSHING IN CONVERTER Sonnax Part Number: 30280-02 Input shaft failure is a common problem in performance GM TH400 transmissions running with added horsepower. OE and aftermarket shafts...

TH400 HD Forward Drum | Sonnax

TH400 Heavy Duty Forward Drum Sonnax Part Number: 34554-01 The ideal GM TH400 upgrade for any power level, Sonnax heavy duty forward drum 34554-01 features a unique combination of high-strength, light weight and a cutting-edge design to optimize...

Powerglide TH400 4L80E HD Clutch Retaining Ring | Sonnax

TH400 4L80E Heavy Duty Clutch Retaining Ring Sonnax Part Number: 28124 Sonnax heavy duty clutch retaining ring 28124 can be used as an upgrade for the Reverse clutch backing plate retaining ring in GM Powerglide transmissions and for the intermediate...

TH400 4L80E Extreme Duty Main Shaft | Sonnax

TH400 4L80E Extreme Duty Main Shaft Sonnax Part Number: 34672-05 Main shaft failure is a common problem in extreme duty GM TH400, 4L80-E and 4L85-E units. OE and aftermarket shafts simply don’t hold up in extreme horsepower applications, leading...

TH400 Extreme Duty Input Shaft | Sonnax | Retro Required

TH400 Extreme Duty Input Shaft  USING THIS SHAFT REQUIRES CHANGING TO A 35-SPLINE TURBINE HUB IN THE TORQUE CONVERTER AND USE OF PUMP COVER BIG SHAFT STATOR SUPPORT TUBE KIT 28154S-125 WITH LARGER INNER DIAMETER Sonnax Part Number: 35280-02 Input...

TH400 Extreme Duty Input Shaft | Sonnax | Pumps Converted to 27-Spline 1-3/16'' Shaft Configuration

TH400 Extreme Duty Input Shaft  THIS SHAFT IS INTENDED FOR USE IN UNITS ALREADY SET UP FOR A 27-SPLINE TURBINE HUB IN THE TORQUE CONVERTER ANDA. PUMP AND STATOR ASSEMBLY CONFIGURED FOR A 1-3/16'' INPUT SHAFT Sonnax Part Number: 27280-02 Input shaft...

TH400 Clutch Volume Spacer Kit | Sonnax | Use w/ 34554-01 Drum

TH400 Clutch Volume Spacer Kit FOR USE WITH HEAVY DUTY FORWARD DRUM 34554-01 Sonnax Part Number: 34554-11K Sonnax heavy duty forward drum 34554-01 is a lightweight upgrade for GM TH400 high performance applications. Significant weight was...

TH400 4L80E MT540 Forward & Direct Clutch Inner Snap Ring | Sonnax | 5-Pack

Allison AT540 AT543 AT545 GM 4L80E Turbo 400 Forward & Direct Clutch Inner Snap Ring Pack-of-5 Sonnax Part Number: 34577-01 NO TOOLING REQUIRED Sonnax forward and direct clutch inner snap ring 34577-01 is a direct replacement for GM 4L80-E, TH400 and...

TH400 Intermediate Sun Gear Shaft | 32-Spline

TH400 Late Design Intermediate Sun Gear Shaft  32-Spline  

TH400 Intermediate Sun Gear Shaft | 28-Spline

TH400 Early Design Intermediate Sun Gear Shaft  28-Spline  

TH400 Smart-Tech® Drum Module for Big Main Shaft | Sonnax

TH400 Smart-Tech® Drum Module for Big Main Shaft FOR RACING APPLICATIONS THAT DO NOT USE FRONT BAND AND RUN A COAN RACING XST 1-1/8'' MAIN SHAFT Sonnax Part Number: 34555-03K Sonnax Smart-Tech drum module for big main shaft 34555-03K upgrades racing...

TH400 Rear Planet Ring Gear w/ Straight Cut Teeth