SunCoast Catagory "4" Allison 6 Speed, Custom Rebuild Kit 950HP (2011-2016) 

Kit contains the following:

SunCoast custom clutch packs
SunCoast custom Steels
SunCoast custom billet plates
SunCoast custom overhaul kit
Valve body calibration kit
SunCoast gasket kit
Pan Filter
Spin on filter
Pan gasket
SunCoast Filter Loc
New internal wiring harness
SunCoast Triple Disc Billet Category 1 Converter
Billet SFI certified Flexplate
Billet Input Shaft
Billet P2 planet assembly
Billet C2 clutch hub
Billet Intermediate Shaft
Billet Output Shaft
Modified Sun Gear
The SunCoast Category kits utilize the latest proven friction materials and steel technology from industry leading companies such as Alto and Raybestos. SunCoast works directly with these companies to design and manufacture proprietary SunCoast exclusive product lines, giving the end user uncompromised quality throughout the entire transmission.

SunCoast has designed these kits in house to exact specifications for many in tents, including but not limited to towing, sled pulling, racing or simply having a vehicle to get from point A to point B.

Designed for light commercial vehicles in both on highway and public transport applications, Allison Transmission's 1000 and 2000 Series are rated up to 400 horsepower from the factory. Allison 5-speed transmission started in 2001 with GM equipped Duramax engines.
Kit Exclusives:



- SunCoast proprietary C1, C2, C3, and C4 Alto carbonite frictions/Rabestos SCZ frictions that contain no center slots. These frictions utilize a waffle pattern in the material to help retain oil helping the clutch cool when not applied.

- Redesigned apply pistons with improved rubber compounds proven to hold higher heat. This custom piston allows us to use a thicker spring apply plate which replaces the thin OEM one that will cone and cause uneven apply surface resulting in premature clutch failure.

- Custom SunCoast apply plate that redirects fluid to better lubricate frictions from the inside out which lubes the entire friction rather than OEM style that lubricates from the center out leaving the inner half of the clutch burnt.

- C5 clutches are not included but can be added to your kit upon request.

- Includes exclusive smart trim / clutch control valve.

- Includes all items needed to modify the C2 clutch piston for increased clutch durability.

The Torque Converter

SunCoast Allison 1000 torque converters come in many varieties, from heavy hauling, sled pulling, drag racing, to daily driving. Here at SunCoast we design and manufacture all of our torque converters in house. Because of this unique advantage SunCoast can supply almost any request in regards to stall speed or torque multiplication. All of our SunCoast Allison triple disc converters are outfitted with a heavy duty forged billet steel cover and give unbeatable lock up performance.

All of the SunCoast Allison 1000 torque converters come standard with custom pump and turbine modifications (in house). SunCoast also Tig Welds each individual furnace brazed fin for improved reinforcement. The SunCoast Allison billet triple disc converter also comes standard with our proprietary trapezoidal clutch teeth.

The Flexplate

This SunCoast Allison billet SFI certified billet flexplate replaces the factory flex plate with an improved billet steel one piece design. This eliminates the weak factory flex plate. This replacement Allsion flex plate is a must with the high torque in conjunction with a better designed torque converter that can transfer torque with no slip. The felxplate is bolted to the crankshaft and then the torque converter 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 Input Shaft

The input shaft is the first thing to go south with the Allison transmission. This Allison billet input shaft is built to withstand everything you can throw at it. This new Allison billet input shaft is manufactured from 9310 Vacumelt steel which increases torsional fatigue strength by over 50%. The SunCoast Allison billet input shaft is machined with a larger radius at the turbine spline for added strength. This a must for vehicles that are lifted with larger wheels and tires, for heavy towing and hauling, and vehicles with aftermarket turbos.

Billet Intermediate shaft

The factory intermediate shaft is one of the last hard parts to break typically on the Allison transmission. SunCoast replaces this shaft on transmission that will be exposed to power levels above 750 horsepower. This new Allison billet intermediate shaft is made from a much stronger 300M billet material. This new billet intermediate shaft also feature an exclusive additional lubrication hole for the P3 sun gear and pilot increasing the life of that circuit. This SunCoast Allison intermediate shaft also has been gun drilled to provide a polished interior finish to eliminate any internal stress risers. This shaft is also heat treated for added strength and reliability.

Billet Output Shaft

The Allison output shaft can be subjected to a tremendous amount of torsional fatigue. This issue can be even more troublesome with heavy towing/hauling or when increasing horsepower and torque. SunCoast replaces the factory Allison output shaft with a billet piece on our Category 4 Allison rebuilds. This new Allison billet output shaft is machined from 300M billet steel and is a direct drop in replacement.

New internal wiring harness

Every build here at SunCoast reliability is our number one priority. Each one of our (Category) Allison rebuild kits comes with a new internal wiring harness. As the transmission continues to age, the plastic connectors become brittle and will break during disassembly. This often leaves builders scrambling around looking for a replacement last minute. This is a new GM harness with all new connectors.

The Billet C2 Clutch Hub

The Allison transmission is an incredibly robust unit, however when exposed to conditions outside what it was designed for weak points begin to expose themselves. The factory C2 clutch hub has been known fail prematurely. This issue is most commonly seen in conditions where larger tire/wheel combinations, heavy towing/hauling, sled pulling, drag racing, and larger shock loads.

SunCoast replaces the factory C2 clutch hub with a much stronger billet piece that is manufactured from 4140 heat treated stress relieved steel. This new Allison billet C2 clutch hub has had the spline lengthened .125 for increased contact area. The spline boss diameter has also been increased .100 for added strength. This Allison billet C2 clutch hub is installed on all SunCoast 700 horsepower category 3 transmissions.

The Billet P2 Planet

The P2 planet with the Allison transmission can strip or snap as a result of poor tuning, shock load, improperly built transmissions and higher horsepower applications. This failure can and will result in catastrophic failure and ore immobility. The SunCoast P2 planet is the solution to the issue. This item is manufactured here at SunCoast using 4140 billet steel that is then induction hardened. This item is highly recommended for higher horsepower applications, including sled pulling, drag racing, as well as heavy duty towing. This planet comes with a machine SunGear which is required for use of the planetary.

The Category Kits

SunCoast Category kits offer our customer the same recipes as our in house builds that have been proven for years both at the track and on the road. Our Category 4 Allison rebuild kit offers the customer our 950+ horsepower Allison rebuild. This rebuild kit includes everything you will need to build your Allison the same we we build here in house. This Allison rebuild kit also includes detailed instructions that will walk you through each step of the process.

SunCoast Allison 1000 torque converters come in many varieties, from heavy hauling, sled pulling, drag racing, to daily driving. SunCoast designs and manufactures their torque converters in-house. Because of this, SunCoast can supply most any request in regards to stall or torque multiplication. All SunCoast triple disc converters are outfitted with a heavy duty forged billet steel cover and give an unbeatable lock up performance. The companys race series converter should be used in racing/pulling applications that require a higher stall RPM than a standard converter. Increased stall is usually needed in applications where a larger turbo or turbos have been installed and more RPM is required to get the turbo on boost while on the brakes (brake boosting).

These HD converters feature a billet stator and will resist damage to the stator section from excessive brake stalling (over 5 seconds).

Standard Features:

Custom pump and turbine modifications (in house)
Tig welding to reinforce furnace brazed fins
Proprietary converter clutches with trapezoid clutch teeth (no round tabs)
Forged billet cover strength (proprietary Raybestos converter)
3 year unlimited mileage warranty