Sun Coast GMAX-CAT3-LLY-0405-4WD Category 3 Transmission & Converter

Ensure your vehicle's transmission can handle increased engine performance when you replace your factory transmission with the Sun Coast GMAX-CAT3-LLY-0405-4WD Category 3 Transmission & Converter. It is crucial to ensure that your transmission can support the additional torque and horsepower produced by engine upgrades. SunCoast transmissions are built with top-notch components that can withstand increased engine power. Upgrading your engine necessitates a transmission that can effectively manage the added power, and SunCoast transmissions are well-suited for this purpose.

SunCoast custom clutch packs

SunCoast custom Steels

SunCoast custom billet plates

SunCoast custom overhaul kit

Recalibrated Valve body 

SunCoast gasket kit

Pan Filter

Spin on filter

Pan gasket

SunCoast Filter Loc

New internal wiring harness 

Billet input shaft

Billet flexplate

Billet P2 planet

Billet C2 clutch hub

SunCoast Triple Disc Billet Converter

The SunCoast Allison billet flexplate is a SFI certified replacement for the factory flex plate. It is made of improved billet steel in a one-piece design to eliminate the weakness of the factory flex plate. This replacement flex plate is necessary when dealing with high torque and a well-designed torque converter for torque transfer without slipping. The flexplate is attached to the crankshaft and then the torque converter is attached to the flex plate. This one-piece billet flex plate is SFI certified to 29.3.

Note: A SFI certified flexplate is required on drag racing vehicles running 11.99 and quicker the 1/4 mile and 7.49 and quicker in the 1/8 mile, or any vehicle exceeding 135mph. In 2008 it was changed from the 29.1 SFI specification to the 29.3 specification for automatic transmissions for diesel applications. The new rules for the flex plate require that the material cannot be stamped metal as are many OEM flex plates.

The initial component to fail in an Allison transmission is the input shaft. This Allison billet input shaft is specifically designed to endure all types of stress. Constructed from 9310 Vacumelt steel, it enhances torsional fatigue strength by more than 50%. The SunCoast Allison billet input shaft features a larger turbine spline radius for increased resilience. It is essential for vehicles with lifted suspension, larger wheels, heavy towing, aftermarket turbos, and extensive hauling.

Every SunCoast torque converter is designed and manufactured in-house. The Allison triple disc converters feature a heavy-duty forged billet steel cover for superior lock up performance. Each torque converter is equipped with custom pump and turbine modifications done in-house. Additionally, SunCoast Tig Welds every individual furnace brazed fin for increased reinforcement. The billet triple disc converter includes proprietary trapezoidal clutch teeth as a standard feature.

The Allison transmission is known for its durability, but it can develop weaknesses when exposed to extreme conditions. The factory C2 clutch hub has a tendency to fail prematurely, especially in cases involving larger tire/wheel combinations, heavy towing/hauling, sled pulling, drag racing, and large shock loads. SunCoast addresses this issue by replacing the factory C2 clutch hub with a stronger billet piece made from 4140 heat treated stress relieved steel. The new Allison billet C2 clutch hub features a lengthened spline for increased contact area and an increased spline boss diameter for added strength. This upgraded Allison billet C2 clutch hub is standard on all SunCoast 700 horsepower category 3 transmissions.

The P2 planet with the Allison transmission may fail due to poor tuning, shock load, improperly built transmissions, and higher horsepower applications. This failure can lead to catastrophic consequences and vehicle immobility. The SunCoast P2 planet is designed to address this issue. It is manufactured at SunCoast using 4140 billet steel that undergoes induction hardening. This product is highly recommended for applications with higher horsepower, such as sled pulling, drag racing, and heavy-duty towing. The planet includes a machined SunGear, which is essential for the use of the planetary.

At SunCoast, reliability is the top priority in every build. Each of their (Category) Allison Transmissions is equipped with a new internal wiring harness. Over time, the plastic connectors in the transmission may become brittle and break during disassembly. This can ultimately result in premature failure.

SunCoast offers exclusive transmissions with proprietary C1, C2, C3, and C4 Alto carbonite frictions/Rabestos SCZ frictions that do not have center slots. These frictions feature a waffle pattern to retain oil and keep the clutch cool when not engaged. Redesigned apply pistons use improved rubber compounds to withstand higher heat. A custom piston allows for a thicker spring apply plate to replace the thin OEM plate that can deform and cause uneven clutch application, leading to premature failure. SunCoast also provides a custom apply plate that directs fluid to lubricate frictions from the inside out for better overall lubrication compared to OEM styles. Additionally, the transmission includes a smart trim/clutch control valve and all necessary components to improve the durability of the C2 clutch piston.

Assembled With Heavy-Duty Components

Can Handle Increased Horsepower & Torque Levels

Improves Known Factory Design Flaws

Comes With Suncoast Torque Converter

Note: Allison CAT 3 700 Hp Trans With Converter 2004-2005 4WD