6L80/90 added check ball

July 29, 2015
A new spacer plate is available for the 6L80 series transmission due to an 8th ball being added to the upper valve body

A new spacer plate is available for the 6L80 series transmission due to an 8th ball being added to the upper valve body (Figure 1). This ball is in what GM designates as the CBR1 hydraulic circuit. This hydraulic circuit feeds the outer diameter area of the Low/Reverse Clutch Piston when reverse and engine breaking low gear is selected (Figures 1 and 2). The two holes in the spacer plate above this ball are identified as 29d and 29e. The new spacer plate has this 29d hole closed down to approximately .054” (Figure 3).

Figure 1
Figure 2
Figure 3
Figure 4

During the application of the clutch, fluid is supplied through both of these holes pushing the ball away from the plate. When the clutch is released, exhausting pressure pushes the new ball onto its seat (29e) forcing the fluid through the .054” hole (29d).

This suggests that the release of the clutch from reverse to park or neutral was producing a clunk type sensation concern. By placing an orifice in the spacer plate with the added ball, this concern is eliminated as it provides a controlled release of the clutch.

The part number for this kit is 24272467 and costs approximately $12.00.

It comes with a new spacer plate, 8 check balls and instructions.

The application is as follows:

2013 – 2015    Cadillac           ATS  

2010 – 2015    Cadillac           CTS 

2010 – 2014    Cadillac           Escalade 

2011                Cadillac           STS

2010 – 2013    Chevrolet        Avalanche 

2010 – 2015    Chevrolet        Camaro

2015                Chevrolet        Colorado

2010 – 2014    Chevrolet        Corvette

2010 – 2014    Chevrolet        Express 

2010 – 2015    Chevrolet        Silverado 

2014                Chevrolet        SS 

2010 – 2014    Chevrolet        Suburban

2010 – 2014    Chevrolet        Tahoe

2015                GMC              Canyon

2010 – 2014    GMC              Savana

2010 – 2015    GMC              Sierra

2010 – 2014    GMC              Yukon  

About the Author

Wayne Colonna | POWERTRAIN PRO Publisher

Wayne Colonna is president of the Automatic Transmission Service Group (ATSG) in Cutler Bay, Fla., and a frequent speaker/instructor for transmission training around the globe.