4L60E, 4L65E, 4L70E Sonnax Pinless Accumulator Piston Kit FWD, 1-2 & 3-4

Symptoms:

  • Aluminum pistons wear at the pin bore
  • Burnt bands
  • Burnt clutches
  • Cracked pistons
  • Delayed engagement
  • Forward Slip

 

Cause:

Wear at the piston pin bore due to repeated reciprocation and/or cracks in the plastic accumulator piston.

The Sonnax patented pinless design with dual seals stabilizes the piston in the bore and provides improved sealing characteristics. Use of the Sonnax part eliminates the need for the pins.

 

Correction:

The Sonnax kit's dual seals stabilizes and completely seals the piston in the bore.

 

 

1 - Pinless Forward Accumulator Piston Kit

Part No.

77987-01K

  • Piston 
  • D-Ring 
  • PTFE Seal 
  • Steel balls (2)

 

2 - Pinless Accumulator Piston Kit 1-2 / 3-4

Part No.

 

77998-03K
  • Pinless Accumulator Piston Aluminum
  • D-Ring Viton® (2)
  • Seal PTFE (2)
  • Balls (4) Steel

Dual Seal design

 

 

 

  • Material: Aluminum

FWD Accumulator Piston:

In GM 4L60-E, 4L65-E and 4L70-E units it is common for the plastic forward accumulator piston to wear or crack. This causes a loss of fluid, resulting in delayed engagement, slips, burnt clutches and/or bands. Repeated reciprocation of the accumulator piston causes the piston pin bore to wear, while fluid loss through the piston pin bore or cracks causes forward clutch to slip. Sonnax pinless forward accumulator piston kit 77987-01K eliminates these problems.

  • Dual seals stabilize and completely seal the bore, providing a tight seal even after thousands of cycles
  • Pinless design eliminates the possibility of pin leakage, and the additional length stabilizes the piston to prevent piston cocking
  • Includes steel balls for plugging existing pin bore in valve body

 

1-2 & 3-4 Accumulator Pistons:

4L60-series units it is common to have poor shift quality, burnt bands or clutches due to accumulator piston wear. Repeated reciprocation of the accumulator piston causes wear at the piston pin bore interface. After this wear reaches a critical point, fluid loss through the piston pin bore cannot be compensated due to lack of pump volume. In addition, the piston can get cocked and gall the accumulator bore due to the pin bore wear or the spring bottoming out. To prevent these conditions in the 1-2 or 3-4 accumulator bores, Sonnax offers pinless accumulator piston kit 77998-03K.

  • Pinless design eliminates the possibility of pin bore leakage and the additional length stabilizes the piston to prevent piston cocking
  • Dual seals stabilize and completely seal the bore and provide a tight seal even after thousands of cycles
  • Steel balls plug existing pin bore in case or cover

 

 

Don't forget to check out Our other eBay store for 
Custom master Heavy Duty Kits or High performance Kits 
They can all be found here World Wide Parts Outlet

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Explanation of Friction plate materials:
We see many different listings on ebay that say Heavy Duty or High Performance on many different listings, it is a little misleading to say the least.

Paper Colors and Information:

Tan, Light brown & Dark Brown

Tan Paper Frictions ARE Stock Not High Performance Not Heavy Duty your Transmission from the factory 
was built with these "photo above Left".


Light & Dark Brown HE "high energy" papers are again stock materials on some but not all Transmissions from the factory. They are an improvement over the tan paper but they are NOT high performance and are NOT heavy duty "photo above Right".




Green/Grey with Graphite Fleck & Black With Graphite Fleck

Green/Grey with Graphite Fleck papers HEG "High Energy Graphite" are an improvement over stock and ARE considered Heavy Duty but NOT high performance.

Green with Graphite Fleck "photo above Left" is High Energy Graphite material.

Grey with Graphite Fleck is a just a Graphite infused Grey paper If it were NOT infused with the graphite is would carry the same grade as the Tan, Light & Dark Brown papers and would not be reliable for heavy duty use. But seeing it is infused with the graphite that would make it acceptable for Heavy Duty use.

Black With Graphite Fleck "photo above Right" ARE considered Heavy Duty and High Performance in any application. It is a carbon infused paper with the addition of graphite VERY Strong.




Blue & Red

Blue plates are sufficient for Heavy Duty use and also high performance "photo above Left".


Red Plates ARE the best material you can buy for ANY Heavy Duty or High Performance application hands down specifically the Red Eagle plates" photo above Right".

 




Information

Shipping:
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for options and additional costs No exceptions.

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item cost and the domestic shipping costs. 
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international shipping costs and any import charges. 




Returns:
30 Day return Money Back or replacement Parts but part or parts must be in good unused condition.


Buyer is to cover cost of return shipping and 15-20% restocking fee for all reasons other than: 

"A manufacturer defects is present or the incorrect parts were shipped from us" .


All returns are handled on a case by case basis.


All returns MUST go through ebay system so RMA # can be given and tracked.


If item or items are under warranty:

Buyer pays nothing for replacement or shipping of new or old parts either direction.


If buyer orders incorrect part or parts, permitting said item or items are not opened or used:

Buyer pays return shipping and a 15-20% restock fee.


If items are installed and used and want to return with no valid reason or warranty issue:

The return will be denied and no credit given. 

Unless approved by staff and would require prior contact before staring the return within ebay.

Need assistance? Call (251) 263-5303

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