29546209 | Genuine Allison® Transmission Push Button Shift Selector

Description: A Push Button Shift Selector 29546209 is an electronic device used in vehicles with automatic transmissions—especially heavy-duty vehicles like trucks and buses—to select transmission modes (like Drive, Reverse, Neutral, etc.) using buttons instead of a mechanical shift lever. Part Number: 29546209 Condition: New Manufacture/Brand: Allison Fits 29546209 For Allison automatic transmissions employing electronic pushbutton shift control systems. Purpose of using 29546209: 1. Ease of Use No manual shifter to move—just press a button to select Drive, Neutral, or Reverse. Especially useful for fleet drivers, bus operators, or inexperienced drivers. 2. Reduced Driver Fatigue Requires less effort and physical movement than a lever or column shifter. Improves ergonomics in large vehicles where the cabin layout may vary. 3. More Accurate Gear Selection Buttons prevent mis-shifting, which can happen with manual or mechanical selectors. Gear selection is done through digital signals, reducing human error. 4. Electronic Integration Works with the vehicle’s electronic transmission control system (TCM). Can be integrated with other systems: Brake interlocks (must press brake before shifting to Drive) Engine control systems (to reduce load on the engine when shifting) 5. Space Saving No bulky shift levers—just a compact button panel. Frees up dashboard or console space in tight cabs. 6. Fewer Mechanical Parts No cables or linkages that can stretch, break, or require adjustment. Improves long-term reliability and reduces maintenance. 7. Safety Features Some systems prevent shifting into Reverse or Park unless the vehicle is at a stop. Protects the transmission from damage caused by accidental or incorrect shifts. Signs of a Bad Transmission Push Button Shift Selector 29546209 1. Won’t Shift into Gear Pressing buttons does nothing—no response from the transmission. Vehicle stuck in Neutral, Drive, or Park. 2. Incorrect Gear Selection Pressing "Drive" might shift into "Neutral" or nothing at all. Selector lights up the wrong gear or none at all. 3. No Lights / Display Malfunction Gear indicator lights don’t illuminate or flicker. LED screen (if present) is blank, dim, or shows error messages (like “--” or “S” for service mode). 4. Delayed Response Noticeable delay between pressing a button and the gear change happening. Especially dangerous when needing quick shifts, like from Reverse to Drive. 5. Intermittent Operation Sometimes it works fine, other times it doesn't—can indicate failing electrical contacts, corroded wiring, or a dying selector unit. 6. Error Codes from TCM Diagnostic scan reveals transmission-related fault codes like: P0705 – Transmission Range Sensor Circuit Malfunction P0880 – TCM Power Input Signal Allison-specific codes like D1, D2, or S on the selector screen. 7. Locked in Limp Mode Transmission goes into "limp mode" (only 1st or 3rd gear available) to protect itself. Often caused by selector, wiring, or TCM communication issues. 8. No Communication with TCM Selector may fail to send signals to the Transmission Control Module (TCM). Could be due to internal failure, power loss, or wiring fault.   About the Manufacturer – Allison: Allison Transmission is a world-leading manufacturer of automatic transmissions and hybrid propulsion systems, primarily used in commercial-duty vehicles. Founded in 1915 and headquartered in Indianapolis, Indiana, Allison is known for producing durable, fully automatic transmissions for trucks, buses, military vehicles, construction equipment, and energy sector applications.