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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
  • SunCoast Triple Disc Billet 4L60/65/70E Converter

The 4L Platform

The 4L60/65/70Eis 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 3 Kit

This Category 3 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 Sonnax Smart Tech Input Housing
Limitations of the GM 4L60-E, 4L65-E, 4L70-E OE input housing are the root cause of 3-4 burnup in performance applications._

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 Sonnax Overdrive Servo

Sonnax 4th gear super hold dual servo kit 77767K features 40% more apply surface area for greater holding power in GM 4L60, 4L60-E, 4L65-E and 4L70-E units. Vehicles with these transmissions often exhibit poor 3-4 shift quality and experience band failure in performance applications. Combine this servo kit with Sonnax 2nd gear servo 77911-03K for unmatched holding power and shift performance that's an easy in-vehicle install.

  • Patented dual-piston design with 40% more apply delivers greater holding power
  • D-ring seals prevent pressure loss

Use with OE, Corvette or Sonnax 2nd gear servo assemblies

The 2nd Gear Servo

The 2nd gear servo is responsible for applying force to the band via hydraulic pressure. One of the first modifications we often see is the switch to the infamous "Corvette" 2nd gear servo. We have learned however that even those have a high failure rate as they were original equipment in the 4L65/70E transmissions. 

In this SunCoast Category Kit we upgrade to the Sonnax Super servo. This servo has an impressive 18% more apply area than the OE "Corvette" servo and features a dual seal design, ensuring a more positive band apply/release and eliminating cross-leaks within the bore.

This new servo is manufactured from billet aluminum and features a chromoly steel apply pin that has added seals to reduce leakage of 3rd gear pressure. This is the fastest band release in the industry.

The Billet Pump Rotor

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.  

Heavy Duty 2-3 Shift Valve
From builders to guys playing in the street, we have all experienced repeated spray vehicles. It is a problem that can ruin the best of plans.
When the GM 4L60-E family of transmissions evolved from the 700-R4, the overrun clutch apply no longer applied in 1st and 2nd when accelerating from a stop in D3 shifter position. This change was made to improve coast-down drivability in D3 but had the side effect of reducing the torque capacity of the input section. For greatly improved input sprag and Forward clutch durability, Sonnax heavy-duty shift valve 77754-41 for 4L60-E, 4L65-E and 4L70-E units will apply the overrun clutch in D3 1st, 2nd and 3rd gears.
Input Drum Reinforcement Kit
The General Motors 4L60/65/70E input drum assemblies have been known to prematurely fail caused by cracking where the input shaft is pressed into it. This is where the overrun piston rides. 
This fracturing can become even more prevalent in units with larger wheel/tire combinations and higher torque units where torsional fatigue becomes even more prominent.
The new Sonnax Input Drum Reinforcement Kit (77733-51K) includes a custom-manufactured overrun piston designed for use only with a stamped steel forward piston, eliminating the need to use aluminum forward pistons.
The Smartest of all Shells
SmartShell® Heavy-Duty Reaction Shell Kit fixes sun gear shell problems with BRAINS, not just brawn.
Bulky aftermarket shells always fall short when splines continue to strip and the shells break under stress. 
A chronic problem with both OE and thicker aftermarket shells is failure of the rear planetary bearing. 
From your daily jobs to extreme builds, the patented SmartShell is the only way to prevent shell failure AND protect the bearing.

Stripped or cracked shells in GM 700R4, 4L60, 4L60-E, 4L65-E and 4L70-E units are a common problem, but strengthening the shell alone does nothing to address the equally common problem of a failed rear planet captured bearing.

Protecting the Planetary Bearing

In the OE sun gear shell, the thrust load passes from the shell through the sun gear, then overloads the small captured planetary bearing. To protect this bearing, Sonnax took the smart approach and replaced the OE black plastic washer with a large thrust bearing and roller clutch race. This re-routes the thrust load directly to the carrier, completely bypassing the delicate bearing.

Strengthening the Shell

The SmartShell avoids the substantially increased weight found in other aftermarket shells. The Sonnax approach to improving the shell includes reinforcing the hub area with a laser beam welded collar. A final machining process after welding ensures precision alignment. The SmartShell splines undergo an advanced machining and heat-treating process, and the lugs which engage the drum are heat-treated as well to avoid flaring.

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

Levels Cycles OEM Manufacturer A
Pressure Required (Lbs./Sq.In.)
OEM Manufacturer B
Pressure Required (Lbs./Sq.In.)
ALTO Red Eagle
Pressure Required (Lbs./Sq. In.)
1 10 64 70 66
1 100 65 71 65
2 10 72 84 74
2 100 73 84 74
3 10 85 96 86
3 100 92 101 93
4 10 102 116 104
4 100 110 122 108
5 10 118 133 117
5 100 124 135 118
6 10 136 148 131
6 100 143 152 134


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."


1 .261 30,232
2 .302 35,048
3 .344 39,865
4 .385 44,681
5 .426 49,498
6 .510 59,131


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.

The Super Servo



Shipping Information

  • Item Requires Shipping
  • 30.0 lbs.
  • W12.0000” x H12.0000” x L10.0000”

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