NHTSA Complaint #11719701 — 2025 LEXUS GX

Vehicle experiences a persistent and abrupt harsh downshift (jerk/thud) specifically during 2nd-to-1st gear transitions when rolling to a stop. This issue persists despite the dealership performing the recommended Transmission Control Module (TCM) software update at 5,000 miles. The smooth shifting returned briefly for approximately 500 miles post-update before the abruptness returned. Additionally, there is a noticeable vibration/harmonic change in the engine as the oil reaches approximately 3,000 miles of use. Concerned that this transmission behavior is a secondary symptom of internal engine drag or main bearing stress, as documented in similar V35A-FTS engine failures. This abrupt downshifting creates a safety concern regarding predictable vehicle deceleration in stop-and-go traffic. Vehicle is currently at 6,700 miles.