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 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...

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 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...

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 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

TH400 Forward Direct Clutch HD Aluminum Piston

TH400 Heavy Duty Forward & Direct Spring Retainer (Pack of 5) by Sonnax 8679934

TH400 Heavy Duty Forward/Direct Spring RetainerPart No. 34554-12OE Part No. 8679934 Package Quantity: 5 Sonnax heavy duty forward/direct spring retainer 34554-12 is ideal for GM TH400 performance applications when stronger release springs are used. OE...

TH400 4L80E 4L85E Reverse Servo Extendo Pin

SKU# T34913SERVO EXTENDO PIN Fits: GM 400 & 4L80E Extend your servo pin length in seconds!

Dipstick Tube Repair End fpr GM, Ford, & Chrysler (Includes Hat Seal) (Can be Braised)

SKU# K35999RFits Ford, Chrysler & GM (with GM hat seal) Made of steel so it can be braised.

TH400 Heavy Duty Billet Intermediate Shaft by TCS

TH400 Heavy Duty Billet Intermediate Shaft by TCS Made from 300M steel. Designed for high horsepower and off-road use. The shaft is a 100% drop-in product. Note* For ultimate performance, combine this shaft with the TCS billet aluminum high drum with...

TH400 4L80E HD Low/Revers Servo Piston | Sonnax | Pre-1996

TH400 4L80E HD Low/Revers Servo Piston (95-Earlier) by Sonnax Heavy Duty Low/Reverse Servo PistonPart No. 34914-01 Fits all TH400 & '95-earlier 4L80-E. OE Part No. 24232745 OE cast aluminum servo pistons can be brittle and are prone to...

TH400 Externally Adjustable Low/Reverse Servo Kit | Sonnax

Designed for GM TH400 racing transmissions, Sonnax externally adjustable low/reverse servo kit 34914-20K makes band maintenance quick and easy. It’s an ideal way to improve reliability and make staging more consistent and predictable. Checking L/R...