I was experiencing a weird binding or lurching in my drive train which made my Subaru feel unstable. I am a mechanic so I investigated these symptoms online and found that a large number of Subaru owners with manual transmissions were experiencing the same issue……a failing viscous coupler was the issue. There were no warning lights or indications prior to failure A failing viscous coupler will not properly engage the front wheels when needed, causing reduced traction in slippery situations, increasing the risk of sliding or spinning out. Uneven power distribution: When a viscous coupler fails, it can lead to uneven power distribution between the front and rear wheels, potentially causing the vehicle to pull or jerk, especially during turns. Sudden engagement: In some cases, a failing viscous coupler might engage too aggressively, causing a sudden jolt or shudder, potentially leading to loss of control. I purchased and replaced this component at my own expense not knowing the magnitude of the issue. This is a definite safety issue that could lead to serious injury or even death. I have the old part in my possession, it failed around 85,000 miles. One of the mechanics in the Subaru forum said he had submitted a report to NHTSA but I didn’t see anything on your sight. Thank you for your help. Sincerely, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)