Sonnax turbine stiffener plate GM-WS-39 is used to create a stronger turbine in GM TH400, Allison AT 540/545, BW 310mm LU (A618) and BW 310mm NLU converters. The design incorporates a contour and reduced outside diameter for optimum fit to the turbine.
The Sonnax plate can be welded as-is to the turbine in GM TH400 and BW 310mm NLU converters, but in Allison AT 540/545 and BW 310mm LU (A618) converters, GM-WS-39 must first be modified.
To weld GM-WS-39 to the turbine, a stock TH350 transmission forward clutch piston may be used as tooling to hold it in place for tacking and welding. Tack welding four to six segments on both the inside and outside diameters of the stiffener plate should be adequate, however some may elect to weld completely around both diameters for maximum strength.

Contour designed for optimum fit to turbine
Enhances strength of turbine
Weld-in-place

More From This Category

Cast Piston

Cast Piston

$92.49

COMP Cams Camshaft, Xtreme Marine, Hydraulic Flat, Advertised Duration 288/304, Lift .570/.575, For Chevrolet Big Block 396-454, Each

COMP Cams Camshaft, Xtreme Marine, Hydraulic Flat, Advertised Duration 288/304, Lift .570/.575, For Chevrolet Big Block 396-454, Each

$591.41

MANLEY Piston, 1.520 in. Compression Distance, 4.600 in. Bore Size, Flat Top, For Chevrolet BB, Each

MANLEY Piston, 1.520 in. Compression Distance, 4.600 in. Bore Size, Flat Top, For Chevrolet BB, Each

$219.04

Motive Gear Getrag 4X4 Rear Seal, Each

Motive Gear Getrag 4X4 Rear Seal, Each

$13.22

QA1 Quick Disconnect Ball Joint, 10-32

QA1 Quick Disconnect Ball Joint, 10-32

$7.78

TCI Torque Converter, Super StreetFighter, 1.85 in. Pilot, For Ford, C-6, Each

TCI Torque Converter, Super StreetFighter, 1.85 in. Pilot, For Ford, C-6, Each

$1,659.53