P0730 on Toyota

On 3rd-generation automatic 4Runners, the internal transmission cooler inside the radiator can rupture and allow coolant and ATF to mix, commonly called the 'pink milkshake.' Once fluids cross-contaminate, the transmission can begin slipping, shuddering, or fail completely. This is heavily documented in owner forums and repair discussions because the damage can escalate quickly if not caught early.

The C-HR's CVT (K120) exhibits noticeable hesitation on acceleration and the typical CVT 'rubber band' effect where engine RPM rises before the vehicle accelerates. The lag between throttle input and forward motion is more pronounced than in competing vehicles.

The Continuously Variable Transmission (CVT) in 2014-2019 Corollas may experience shuddering, jerking during acceleration, high RPM before shifting, and in severe cases complete transmission failure. Issues are particularly reported when accelerating from a stop or during downshifting. Some owners have experienced catastrophic failures at relatively low mileage.

The intelligent Manual Transmission (iMT) rev-match system can interfere with smooth shifting, causing unexpected RPM blips and a disconnected shift feel. The system sometimes over-revs or under-revs during downshifts, and the clutch pedal feel is reported as vague.

GR86 models with the 6-speed manual develop throw-out bearing noise, typically a chirping or squealing sound when the clutch pedal is depressed or released. The bearing wears prematurely, especially in stop-and-go traffic. Not an immediate failure risk but worsens over time.

The UA80E/UA80F 8-speed automatic in V6 Highlanders can develop a whine or grind noise traced to defective front carrier assembly pinion shafts/bearings. As the bearings delaminate they shed metal debris through the fluid, which can progressively damage the torque converter and transaxle internals. This is a hard mechanical failure distinct from the more common torque-converter shudder/hesitation driveability complaint, and Toyota's prescribed repair is full transaxle replacement.

Toyota T-SB-0107-19 Rev1 documents a narrow hesitation condition on some 2019 RAV4s: vehicle speed is 6 mph or below, the event occurs immediately after a 3-to-1 downshift, and accelerator input is below 40 percent. Toyota modified ECM logic to reduce that behavior. This is not evidence of a 2019-2023 CVT magnetic-clutch defect, and the bulletin does not use the prior P0700/P0730/P0740/P0868/P17F0/P17F1 list as eligibility criteria. Hesitation outside all three conditions requires normal engine, fuel, brake and transmission diagnosis.

The ZF 8HP51 automatic transmission exhibits rough or jerky shifts at low speeds, particularly 1st-to-2nd and 2nd-to-3rd gear changes during city driving. The mechatronic unit's valve body can develop wear causing harsh engagement. Cold weather worsens symptoms.

The 6-speed manual transmission can exhibit grinding when shifting, particularly into 2nd or 3rd gear, and generally notchy shift feel. This is often related to the synchros or the clutch system hydraulics.

The Mazda-sourced 6-speed automatic in the 2016-2018 Yaris iA and 2019-2020 Yaris sedan (a completely different unit from the Toyota U340E 4-speed in the hatchback) draws consistent owner complaints of a whistling or whining noise during the 1-2 and 2-3 upshifts, plus a grinding or clunking noise when selecting Drive from Park. Reports range from a noise-only nuisance to units replaced under warranty, and a few owners describe progression to gear slippage and a stall with audible metal-on-metal. Because this transmission uses a very small lock-up-early torque converter for economy, converter shudder and fluid degradation show up earlier than owners expect for a Toyota-badged car.