SUNCOAST ALTO 4L60/65/70E CATEGORY 4 REBUILD KIT

This 4L60E Rebuild Kit Includes the Following:

• New 4L60E Overhaul Kit
• Alto Red Eagle Clutch Kit with Power Packs
• High Performance Kolene Steel Kit
• New 4L60E Filter
• New 4L60E Bushing Kit
• New 4L60E Thrust Washer Kit
• Sonnax 4L60E Performance Pack
• Sonnax Rear Stator Support Bushing
• Sonnax Oversized 2nd Gear Servo
• Borg Warner Upgraded 29 Element Sprag
• Sonnax 1-2 Pinless Accumulator Piston Kit
• Sonnax .490 Larger Boost Valve
• High Output Pump Slide Spring
• 4th Gear Servo Return Spring
• Sonnax Heavy Duty Smart Shell Kit
• Sonnax Heavy Duty Shift Valve
• Sonnax Input Drum Reinforcement Kit
• Sonnax Smart Tech Input Housing Kit
• 13 Vane Billet Pump Rotor
• Upgraded Billet Input Shaft
• Upgraded Billet Output Shaft
• SunCoast Triple Disc Billet 4L60/65/70E Converter

The 4L Platform

The 4L60/65/70E is a series of automatic transmissions from General Motors. Designed for longitudinal engine configurations, the series includes 4 forward gears and 1 reverse gear. The 4L60E is the electronically commanded evolution of the Turbo-Hydromatic 700R4, originally produced in 1982.

Most of the 4L60/65/70Es you see in service today were originally manufactured in the Toledo, Ohio, plant for General Motors.

These transmissions cannot be differentiated from the outside by the average eye. The 4L65E shares the same exterior parts but has stronger internals, such as 5 pinion planets compared to 4 in the 4L60E. These also can carry several different input shafts depending on which version you have. The early 4L60Es had a 298mm input shaft for non-LS platforms while the later LS models utilized a 300mm one. The later 4L70E also utilized an input speed signal on the input shaft.

An updated 4L60E, the 4L65E (RPO M32), was phased in the 2001 model year when coupled behind the 6.0 Vortec. Five-pinion front and rear planetaries, along with an additional 3-4 clutches, allowing 7 clutches in the input housing and induction-hardened input shaft assembly, were improved to withstand up to 380 ft-lbs (515 N-m) of torque.

The Category 4 Kit

This Category 4 SunCoast 4L60/65/70E kit has everything you need for a successful high performance rebuild. This kit was designed for customers looking for a complete solution to their 4L60/65/70E transmission issues. Aside from all-new electronics, these kits include the same recipe we build with at SunCoast daily.

The Output Shaft

Output shaft failure is common as power levels are increased in GM 4L60-E, 4L65-E and 4L70-E units. This upgraded shaft is precision engineered and manufactured for unbeatable performance in high-horsepower street and strip builds. The shaft features many unique refinements available, including a torsional design that allows energy to be absorbed, reducing peak loads to critical areas.

• High-strength 300M steel shaft with rolled splines
• Specially heat-treated and processed for maximum toughness

Torsional design absorbs energy, reducing peak loads to critical areas

The Input Shaft

Input shaft failure is a common problem in GM 4L60-E, 4L65-E, 4L70-E units as power levels are increased. This upgraded input shaft is ideal for any high-horsepower street or strip application. The shaft is manufactured from a specially heat treated steel with very hard outer layers and a more ductile inner core for strength and resistance to fracture. The feed holes are chamfered to reduce stress, and the shaft is further processed by shot peening and deep cryogenic treatment.

• High-strength steel ideal for high performance applications
• Shot peened and cryogenically treated for extreme durability
• Unique design protects against failure from stress cracks

The weak OE backing plate flexes during clutch apply, allowing heat to build up unevenly within the clutch packs limited space. 

Sonnax Smart-Tech input housing kit 77733-06K makes room for a taller clutch pack anchored in place by a stronger backing plate, making it the only way to increase clutch capacity and protect against destructive heat. Numerous other improvements to the housing ensure maximum durability and protection against failure in higher horsepower, higher pressure applications. The housing also is available with a pre-installed, heavy-duty input shaft.

Physically larger clutch pack area for increased 3-4 clutch capacity without sacrificing clutch durability. Use your choice of:

•  Eight .067" frictions with seven .095" steels
•  Nine .062" frictions with eight .077" steels
•  Anchored backing plate keeps clutches parallel to stop the flexing and distortion that leads to heat build-up
•  Treated housing is significantly more resistant to fatigue failure
•  Steel reinforcement sleeve prevents breakage in the spline area
•  Custom backing plate replaces OE retaining ring to eliminate risk of blowout

The 700R4/4L60/65/70E platforms are notorious for pump cavitation at higher rpms. A typical solution would be to increase pump vanes to allow more fluid volume to be dispense. 

The problem lies that as I increase pump vanes the material between vanes is significantly less and less. With cast material this can be a critical failing point. In this Suncoast category kit we are replacing the factory cast piece that is also know for premature failure with a full precision machined billet 13 vane pump rotor. 

This pump rotor not only increases fluid volume but adds the reliability and strength needed in a high performance build.

The Apply Band

The 4L60/65/70E transmissions utilize an apply band when shifting from 1st to 2nd and again when shifting from 3rd to 4th. This band is wrapped around the reverse input drum that sits directly behind the front pump assembly.

This band is known to be the weakest link in this unit, a problem that becomes even more prominent when you start deleting torque management or adding power modifications. Here at SunCoast with our 4L60/65/70E transmission rebuilds, we use a High Performance Alto Red Eagle Wide Band with reinforced band anchors to improve reliability and performance. 

The Performance Pack

The Sonnax Performance Pack for GM 4L60E, 4L65E and 4L70E transmissions is a must-have for any heavy-duty vehicle and the very best foundation for high-performance racing. All components work together to carefully tune line pressure, accumulator pressure and shift calibration. It’s the ultimate way to get an impressive transmission that responds to throttle and increased load with quick, firm shifts.

Rear Stator Support Bushing

The original GM 4L60, 4L60E, 4L65E, 4L70E rear stator bushing comes in narrow and wide versions in both common bronze and harder aluminum type materials. All versions commonly fail or wear out prematurely. Available aftermarket replacements typically have a poor quality fit and are also known to wear.

For maximum durability, Sonnax offers rear stator support bushing 77002BT-01, a better fitting and extremely wear-resistant, PTFE-lined bushing to stop future wear in its tracks.

The Sonnax bushing is the best option for supporting the 20 lb. input housing and for improving the reliability of these common units.

The Sprag

The factory sprag assembly is notorious for flipping and, as a result, causing catastrophic failure to your 4L60E transmission that could be fairly expensive to repair.

This SunCoast 4L60E transmission category rebuild kit comes with an upgraded Borg Warner 29-element sprag with a dual cage design. This dual cage design allows the 29 elements to apply in a more even manner, eliminating the elements from flipping.  

The Clutch Kit

This is a complete 4L60/65/70E super rebuild kit containing Alto Red Eagle clutches, with the 3-4 clutch pack that includes 8 clutches. This kit will include everything else you need to rebuild your 4L60E transmission. A new filter is included, as well as a bushing kit and thrust washer kit. The band in the kit is a high performance Red Eagle band. 

Alto Red Eagle^® material offers similar mid-point coefficient at high horsepower applications. In addition, the Alto Red Eagle® material gives superior friction wear characteristics at high energy engagements. The leading competitor's material degrades thermally and physically after reaching approximately 2.25 HP/in2. 

Below we offer some engineering data collected with this particular clutch.

Six Level High Energy Test
On Frictional Properties And Wear

Lbs./Sq. Inch Pressure Required To Stop Flywheel In One Second

NOTE: The Lower Lbs./Sq.In. Required to stop the flywheel, the higher the frictional properties.

Results: Pressure required to stop the flywheel on "ALTO RED EAGLE" are slightly lower than "Manufacturer A" and well below "Manufacturer B."

Conclusion: The frictional properties of "ALTO RED EAGLE" are slightly higher than "Manufacturer A" and well above "Manufacturer B."

Test Schedule and Duration:
Test conducted in six energy levels. Each level consists of 100 clutch engagements at 60 second intervals, from 4600 RPM with a clutch lockup time of one second, the indicated pressure required to stop the flywheel in one second.