D Group 28 Design and Function MID 130 Transmission Control Unit The “Premium Tech Tool” (PTT) is the preferred tool for performing diagnostic work. Contact your local dealer for more information. System Overview The I-Shift transmission is a technologically advanced automated mechanical transmission, designed specifically to work in conjunction with Volvo’s new family of heavy-duty diesel engines. In order to work as a total package, the I-Shift is programmed with each engines’ efficiency map and is offered with different software options to fulfill each operators needs.
The I-Shift uses compressed air and electrical solenoids to perform shift functions, clutch control and countershaft brake functions. All of these functions are timed and controlled by the Transmission Electronic Control Unit (TECU). A dedicated air tank is needed on the vehicle to supply air for these components. The air is plumbed to the transmission via a supply line and is distributed to the other components internally. The air control solenoids are housed in the Transmission Control Housing and in the Clutch Control Valve Assembly. All variants of the Volvo I-Shift have 12 forward speeds and up to 4 reverse speeds depending on programming.
It is a single countershaft transmission built up with a splitter section, a main section with three forward and one reverse gear, and a range gear section. It is an automated mechanical transmission and uses synchronizers in its splitter and range gears but not in the main section. The main section utilizes a countershaft brake to mesh gears and equalize shaft speeds as needed. A single disc automated clutch system is utilized. The I-Shift is a "two pedal" transmission and does not require a clutch pedal. All Volvo Truck models will be available with this transmission including the VT, VN Series & VHD vocational trucks.
Four I-Shift models will be offered to support the power ranges of the engines as well as offering different gear arrangements: Transmission Identification Each transmission has two identification tags. One is found on the top of the clutch housing and the other is found on the back of the range housing. The transmission version can be readily identified by the following nomenclature table.
8 AT2512C ATO2512C AT2812C ATO3112C Operation Two Pedal Two Pedal Two Pedal Two Pedal Forward Speeds 12 12 12 12 Engines Available D11/D13 D11/D13 D16 D16 Overall Ratio 14.94:1 15.04:1 14.94:1 15.04:1 Top Ratio Direct 1.00:1 Overdrive 0.78:1 Direct 1.00:1 Overdrive 0.78:1 Weight lbs (kg) 597 (275) 597 (275) 610 (281) 610 (281) Make Volvo Type AT2512C, ATO2512C, AT2812C and ATO3112C Description A — Automatic T — Transmission O — Overdrive 25 — Torque Capacity 2500 Nm (1850 lb/ft) 28 — Torque Capacity 2800 Nm (2050 lb/ft) 31 — Torque Capacity 3100 Nm (2300 lb/ft) 12 — Number of forward gears C — Design Level