Suncoast CAT3 700 HP CUSTOM ALLISON TRANSMISSION WITH CONVERTER (GMAX-CAT3-LB7-0103-2WD) for 2001-2004 Duramax LB7

Sun Coast Allison 1000 Performance Transmission Components

This Sun Coast Allison transmission upgrade package strengthens the most common failure points found in factory Allison transmissions. Designed for Duramax trucks used in towing, high horsepower builds, and competition applications, these upgrades increase durability, torque capacity, and long-term reliability.

Sun Coast engineers each component to withstand the higher torque loads created by tuning, upgraded turbos, larger tires, and heavy trailers. As a result, the transmission remains reliable even under extreme driving conditions.

Billet Flexplate

The Sun Coast billet flexplate replaces the factory stamped flexplate with a stronger one-piece billet steel design. This eliminates a known weak point in many stock drivetrains.

The flexplate connects the crankshaft to the torque converter and must withstand extremely high torque loads. The Sun Coast flexplate is SFI 29.3 certified, meeting the current safety requirements for high-performance automatic transmission applications.

SFI certification is required for many racing vehicles running 11.99 seconds or faster in the quarter mile, 7.49 seconds in the eighth mile, or exceeding 135 mph.

Billet Allison Input Shaft

The Sun Coast billet input shaft addresses one of the most common failure points in the Allison transmission. The factory shaft can fail when exposed to increased torque levels from performance tuning or heavy loads.

Sun Coast manufactures this upgraded shaft from 9310 Vacumelt steel, increasing torsional fatigue strength by more than 50 percent. The shaft is also machined with a larger radius at the turbine spline for added durability.

Triple Disc Torque Converter

Sun Coast designs and manufactures its Allison 1000 torque converters in-house. This allows precise control over stall speed and torque multiplication for different driving conditions.

Each triple disc converter features a forged billet steel cover and provides strong lock-up performance under heavy load. Sun Coast also TIG welds each furnace-brazed fin for added reinforcement.

These converters include proprietary trapezoidal clutch teeth that improve clutch engagement and durability during high torque operation.

Billet C2 Clutch Hub

The factory C2 clutch hub can fail when exposed to higher torque loads. This issue often appears in trucks with large tires, heavy towing setups, sled pulling applications, or aggressive tuning.

Sun Coast replaces the factory hub with a billet C2 clutch hub manufactured from heat-treated 4140 steel. The spline length is increased by .125 inches to improve contact area, and the spline boss diameter is increased by .100 inches for added strength.

Billet P2 Planetary Assembly

The P2 planetary gear set can strip or fail when exposed to shock loads or high-horsepower setups. When this occurs, it can cause severe transmission damage.

Sun Coast solves this problem with a billet P2 planetary assembly manufactured from 4140 steel and induction hardened for durability.

New Internal Wiring Harness

Each Sun Coast transmission build includes a new internal wiring harness. Over time, factory wiring connectors can become brittle and break during service.

Replacing the harness during the build process ensures reliable electrical operation and helps prevent premature transmission failures.

Transmission Package Includes

Sun Coast custom clutch packs
Sun Coast custom steels
Sun Coast billet clutch plates
Sun Coast custom overhaul kit
Recalibrated valve body
Sun Coast gasket kit
Pan filter
Spin-on filter
Pan gasket
Sun Coast Filter Loc
New internal wiring harness
Billet input shaft
Billet flexplate
Billet P2 planetary assembly
Billet C2 clutch hub
Sun Coast triple disc billet torque converter