Starting in 2011, along with the LML Duramax, the Allison went through several significant updates as well. One of the most important of which was the change from a static/fixed line pressure setting to an electronically-variable line pressure control via the third accumulator in the updated valve body.
What this means, is that unlike 2001-2010 Allison 1000 series transmissions, the TCM now has control over line pressure and can vary it based on driving conditions and shift points. This is ideal for fuel economy (lower line pressure during steady-state cruising means less parasitic load on the transmission pump) and lower transmission temps (fluid under higher pressure generates more heat).
During steady-state cruising, the transmission runs a very low 80psi of mainline pressure. During a shift, the TCM will spike line pressure to ~250psi in order to prevent slipping during the clutchpack handoff. But once the shift has been completed, the TCM drops line pressure down again. This is NOT ideal for trucks that are running tuners which increase the horsepower level to the point where the low line pressure simply cannot provide enough holding power and the clutches begin to slip, resulting in transmission damage.
The BT DieselWorks transmission line-pressure controller for the 2011+ Allison 1000 series allows you to take full manual control of transmission line pressure at any time without having to deal with any driveability issues, limp modes, or nuisance check engine lights.
This module will allow the transmission to hold extra power safely during racing/pulling, without risk of burning the clutchpacks.
The module has three selectable modes of operation:
1. "stock" (factory mode; TCM controls line pressure)
2. "full pressure" (constant forced maximum line pressure)
3. "Automatic" (runs stock TCM-controlled line pressure until above ~90% throttle, when the module automatically forces the transmission to maximum line pressure)
The Automatic mode is ideal for daily driving because it is a "set it and forget it" convenient way to keep the transmission running cool, keep your fuel economy up, while still providing that automatic "boost" in power holding capability when you want to hot-rod the truck.
Installation is simple, and the module comes with a convenient dash-mountable indicator light to let you know at a glance what the current status of line pressure and module operating mode is. Installation instructions are available for download in the "INSTALLATION GUIDES" link at the top menu bar of the website.
NOTE: 2015.5+ trucks use different color wires and different locations at the TCM connector! If you have a 2015 truck and are not sure if it is a 2015 or 2015.5, check your glove box RPO-code sticker. If you see the code "AVF", you have a 2015.5 truck.