Sonnax Smart-Tech drum module 34555-01K for racing GM TH400 transmissions improves on-track performance and consistency, leading to quicker ETs, more wins and greater reliability.
The TH400 is preferred for its overall durability and multitude of available ratios, but is known to be heavier and less efficient than the popular two-speed Powerglide. Part of the TH400 inefficiency results from the fact that the direct drum counter rotates, spinning backwards in 1st Gear, brakes to a complete stop on the 1-2 shift, then goes from 0 RPM to input RPM on the 2-3 shift. Significant energy is wasted through this cycle that robs power, upsets traction on the shifts and contributes to broken internal parts.
Compared to aluminum direct drums, the Smart-Tech drum module reduces the weight of the counter-rotating components by over 3.3 lbs! And more significantly, because the weight of the Sonnax counter-rotating parts is closer to the centerline, there is a 68% reduction in energy required to stop and restart during the 1-2 and 2-3 shifts. The benefits are increased wheel horsepower, better acceleration, less shock on the shifts and improved durability.
- Complete kit replaces both forward and direct drums and includes everything from intermediate sprag to the pump; a selection of Sonnax input shafts is available separately
- 100% new content, no used core pieces
- Includes larger-diameter, 36-element sprag and sprag race that works with OE intermediate clutches
- Includes six-friction forward clutch pack and seven-friction direct clutch pack
- Forward Piston Housing
- Forward Piston
- Forward Piston Return Springs (16)
- Forward Spring Retainer
- Forward Snap Ring
- O-Ring 1.674"
- Lip Seals (2)
- Direct Housing Assembly
- Direct Piston
- Direct Piston Return Springs (26)
- Direct Spring Retainer
- Direct Snap Ring
- O-Ring 2.737"
- Sprag Shaft
- Front Sprag Retainer Plate
- Heavy Duty Sprag 36 Element
- Outer Sprag Race
- Rear Sprag Retainer Plate
- Sprag Retainer Screws (4) 6-32 x 5/16"
- Quad Ring Seals (2)
- Anti-rotation Seal Rings (2)
- Drum
- Pressure Plate
- Outer Snap Rings (4)
- Bearing Small
- Forward Clutch Hub
- Bearing Large
- Direct Clutch Hub
- Steel Clutch Plates (4) .060"
- Steel Clutch Plates (11) .077"
- Friction Clutch Plates (13) .080"
- Clutch Separators (60) .103"
APPLICATIONS
AMC
Wagoneer 1965-1979
Buick
Century 1973-1974
Century 1977-1979
Electra 1965-1975
Electra 1978-1979
Electra 1980-1981
LeSabre 1965-1971
LeSabre 1972-1976
LeSabre 1978
LeSabre 1980-1981
Riviera 1965-1976
Riviera 1978
Skylark 1973-1976
Cadillac
DeVille 1973-1984
Fleetwood 1974-1984 (3 speed RWD)
Chevrolet
Blazer 1978-1979 (3 speed RWD)
Camaro 1967-1974 (3 speed RWD)
Caprice 1974-1976 (3 speed RWD)
Chevelle 1967-1975
Corvette 1967-1977
Malibu 1972-1975
Nova 1972-1973
Nova 1975
Truck 1965-1990 (3 speed 4x2)
Truck 1977-1990 (3 speed 4x4)
Van 1975-1990 (3 speed)
GMC
Jimmy 1978-1979 (3 speed RWD)
Sprint 1971-1975
Holden
Holden 1975-Up
Jaguar
XJ12 1977-1981
XJS 1978-1980
Oldsmobile
Cutlass 1973-1977
Olds 98 1972-1981 (3 speed RWD)
Pontiac
Bonneville 1974-1977
Catalina 1974-1977
Firebird 1967-1976 (3 speed RWD)
LeMans 1972-1977 (3 speed RWD)
Tempest 1967-1971 (3 speed RWD)
Rolls Royce
Bently 1967-up
Silver Spur 1968-1990
Siver Shadow 1968-1990
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