PPE 128041119 EPC Solenoid Blocker (2011-2019 6.6L Duramax)

Fitment

Fits 2011-2019 Chevrolet Silverado 2500HD and 3500HD and GMC Sierra 2500HD and 3500HD with the 6.6L Duramax and Allison 1000 transmission. That covers the LML (2011-2016) and 2017-2019 L5P trucks. The 2011 change was the TCM taking electronic control of mainline pressure, which is why this part is listed for 2011-2019 only. Per PPE, the blocker makes mainline pressure fully available in all driving conditions, like the 2001 to 2010 Allison 1000 transmissions. Verify by VIN or call us. More Duramax parts.

Why this part

Mainline pressure is created by the transmission's oil pump. The valve body directs it to the applied pistons, and that pressure is what clamps the clutch packs quickly and completely. When mainline pressure is low, or isn't there at the right time, clamping force drops and the clutches can't hold the engine's torque. Clutch packs that slip generate excessive heat, and that heat destroys the clutch pack material.

The EPC circuit's job is to modulate mainline pressure. In a 2011-2019 Allison 1000, mainline pressure varies from 80psi to 230psi depending on driving conditions. Get on the throttle to accelerate and it rises from 80 psi up to 230 psi; after the shift it drops back to 80 psi. At 80 psi the clutch packs have barely enough clamping force to hold the engine's torque, and the EPC circuit is too slow to close and let pressure build. The result is clutch plate slippage and premature wear. GM's 2011-and-later TCM drops line pressure to about 80 psi at cruise to save fuel, and modified trucks slip clutches unless TCM tuning raises it. The blocker is the mechanical alternative.

What PPE says the blocker does:

• Increase clamping force to clutch packs
• Improve shift quality
• Increase ability to hold more horsepower
• Easy to install
• Easy alternative to transmission line pressure tuning

What you get

• One PPE 128041119 EPC solenoid blocker, which installs between the EPC solenoid and the valve body

Specifications

• Application: 2011-2019 Allison 1000 behind the 6.6L Duramax
• Stock mainline pressure: 80psi to 230psi, depending on driving conditions
• With the blocker: all available mainline pressure, up to 230 psi, at all times
• Mounting location: between the EPC solenoid and the valve body

Installation notes

The EPC blocker kit installs quickly between the EPC solenoid and the valve body, and there is no need to remove the valve body. Drain the transmission fluid, remove the oil pan and install the EPC blocker. Once it is in, all the available mainline pressure, up to 230 psi, reaches the applied pistons and clutch packs at all times. For the refill, GM's fluid spec for the 2011-2016 Allison is DEXRON VI.

About PPE

PPE, Pacific Performance Engineering, has been around since 1985 and is based in North Las Vegas, Nevada. The company built its name on 6.6L Duramax parts, and transmission parts are a core line, from cast aluminum deep pans and filters to coolers and performance mounts. It also covers Ram Cummins and Ford Powerstroke trucks. Shop PPE parts.

Frequently asked questions

Do I have to remove the valve body to install it?

No. Drain the fluid, drop the pan and install the blocker between the EPC solenoid and the valve body. The valve body stays in the transmission.

Is this the same as TCM tuning?

No. It is a mechanical part that PPE sells as an easy alternative to transmission line pressure tuning. TCM tuning for 2011-and-later trucks raises cruise line pressure and firms shifts in software. The blocker gets all available mainline pressure, up to 230 psi, to the clutch packs without changing the calibration.

Does my 2001-2010 Duramax need one?

It is not listed for those years. Per PPE, the 2001 to 2010 Allison 1000 already had mainline pressure fully available in all driving conditions; the blocker brings the 2011-2019 transmission back to that behavior.

Questions on fitment? Call the shop at the number in the header. We install everything we sell.