SQ5 Transmission Trouble: Rough Shifts & Slipping Gears

I had a very similar issue with my 2016 S4. Based on my experience with automatic transmissions, these symptoms often point to gear wear in the transfer case. When I first noticed rough shifts and inconsistent power delivery, I initially thought it was just the gear oil needing replacement. However, after taking it to the workshop, they diagnosed defective gears in the transfer case, which was causing the grinding and slipping sensation during acceleration. The repair involved replacing several worn components in the transfer case and doing a complete transfer case oil change. Total cost was 330 Euro, which included parts and labor. The difference in transmission performance after the repair was significant, smooth shifts returned and the slipping completely disappeared. Before suggesting specific solutions, could you share: Current mileage on your SQ5? When was the last transmission service performed? Are you noticing any unusual sounds along with the shifting issues? Does the problem get worse after the car warms up? This information would help determine if your issue matches what I experienced and whether you might be facing similar transfer case problems.

Thanks for confirming my suspicions about the transfer case. My SQ5 has 132546 KM on the odometer, and the gear oil and transfer fluid were last changed during the standard service 15000 KM ago. The shifting issues do get noticeably worse after warm-up, usually about 15 minutes into driving. Recently started hearing a faint whining noise during acceleration, which makes me think the transfer case oil leakage you mentioned could be the culprit. Seeing your repair costs gives me a good reference point for what to expect at the workshop. Will get it checked soon since driving with compromised transfer case components could lead to more expensive repairs down the line.

Thanks for providing those details. The symptoms you describe, especially the whining noise during acceleration and worsening performance when warm, match exactly what I experienced with my S4 before the repair. The combination of rough shifting, whining sounds, and degraded performance after warming up strongly indicates gear wear in the transfer case. In my case, waiting too long led to increased transfer fluid leakage and eventually damaged multiple gear components. Given your mileage and the fact these issues developed after a recent fluid change, I suspect your transfer case may have internal wear that fresh oil alone cannot fix. When my S4 showed these symptoms, we discovered microscopic metal particles in the transfer fluid, confirming internal gear wear. Looking back, I recommend getting it checked soon. My repair costs would have been closer to 200 Euro if I had addressed it when the whining first started. The grinding got significantly worse over just a few weeks of continued driving. Would suggest having them specifically check: Transfer case fluid condition and level, Internal gear wear patterns, Transfer case seals integrity, Input shaft bearing condition

Just got back from the workshop and wanted to close this thread with an update. The mechanic confirmed what you suspected, mechanical wear in the transfer case was causing the issues. They found metal particles in the gear oil and significant wear on several components. Total repair included replacing worn gears, addressing the oil leakage around the seals, and a complete fluid change. Final cost came to 380 Euro, slightly more than your case but still reasonable considering the extensive work done. The transmission now shifts perfectly smooth again and that annoying whining noise during acceleration is completely gone. Really glad I addressed this before the transfer case damage got worse. The workshop mentioned that continuing to drive with these symptoms could have led to complete failure and much costlier repairs. Thanks again for helping identify the issue. This thread should help others who experience similar transfer case problems with their vehicles.