The Allison Transmission HT 750DR Preventive Maintenance Manual is a comprehensive guide designed to ensure the safe and reliable operation of your heavy-duty truck transmission. This manual details the essential service procedures recommended by Allison Transmission, providing effective methods for performing maintenance operations. The manual covers a wide range of topics, encompassing both removal and installation procedures.

**Section I: Removing Transmission From Vehicle** delves into the process of disconnecting controls, uncoupling from the driveline and engine, and carefully removing the transmission. It also provides instructions for removing the input and output flange, as well as guidance on rebuild and overhaul procedures.

**Section II: Preparing Transmission For Installation** covers vital steps such as checking the flywheel, installing brake and output flange, and installing the input flange, range selector lever, PTO, and shift modulation control. It also guides you on installing the oil filler tube.

**Section III: Preparing Vehicle For Transmission Installation** focuses on inspecting components like the flexplate drive assembly, input drive components, chassis and driveline, oil cooler, oil filter, and lines, and checking the controls.

**Section IV: Installing Transmission Into Vehicle** provides detailed instructions on handling the transmission, mounting it to the engine, installing mounting components, coupling to the engine and driveline, and connecting various control systems, including the oil cooler, oil filter, range selector, hydraulic retarder, modulator, power takeoff, parking brakes, output disconnect, speedometer drive, and temperature and pressure sensors.

**Section V: Oil System** delves into the intricacies of filling the oil system, understanding the oil pan and its interchangeability, obtaining spare parts information, and installing the oil pan assembly and oil filler tube. The manual further provides guidance on checking the oil level, interpreting oil specifications, performing oil changes and filter replacements, and managing oil operating temperatures.

**Section VI: Dual Mode Operation** explains the functional operation of the dual mode system, covering installation, downshift inhibiting procedures, and the operation of the CLBT 750 Dual Mode Transmission.

**Section VII: Release of Step Governor Valve Body Assembly** provides information on the release of the step governor valve body assembly, including interchangeability and spare parts information.

**Section VIII: Manual/Automatic Operation On Oil Field Equipment** covers the general operation of manual/automatic transmissions on oil field equipment, providing details on the Mannesmann Rexroth and Bennett shifters, preventive maintenance procedures, and mode shift valves used in these systems.

**Section IX: Troubleshooting CLBT 750 With Dual Mode** provides guidance on pressure tap location, troubleshooting dual mode circuitry, and understanding the function of the step governor valve.

The Allison Transmission HT 750DR is a robust and reliable automatic transmission designed specifically for heavy-duty trucks operating in demanding applications. Renowned for its durability and performance, the HT 750DR is a key component in various commercial trucking operations. This transmission boasts an impressive combination of power, efficiency, and longevity, making it a favorite among fleet operators and drivers alike. The HT 750DR is distinguished by its advanced design, featuring a robust planetary gear set capable of handling high torque and heavy loads. The transmission's proprietary electronic controls optimize gear selection and shifting patterns, resulting in smooth and efficient power delivery. Its advanced features include electronic shift control, torque converter lock-up, and multiple gear ratios, providing drivers with optimal performance across varying road conditions and payloads.

The Allison HT 750DR transmission is a testament to Allison Transmission's dedication to innovation and engineering excellence. Its robust construction and advanced electronic control systems ensure reliable operation in even the most challenging environments. The HT 750DR is engineered with durability in mind, featuring high-quality components and wear-resistant materials. This transmission is designed to withstand the rigors of heavy-duty applications, minimizing downtime and maximizing productivity. The HT 750DR's reputation for reliability has made it a preferred choice for a wide range of applications, including long-haul trucking, construction, and mining. The transmission's ability to handle demanding loads and perform consistently over extended periods makes it an invaluable asset for businesses reliant on efficient and dependable transportation.