Shift flares and reverse issues
Scion TC and xB models that use a 4-speed automatic transmission, designated as U241E, can suffer from several different issues. In most cases, there will be severe slips or flares, with gear shifts between the 2nd and 3rd gear being most noticeable.
This can also be accompanied by delays and failures when engaging in reverse or TCC lockup issues. None of these problems will trigger a check engine light.
Grinding noise or vibrations while driving
- Excessive bore wear inside the solenoid modulator valve happens due to continuous movements of the valve itself and resulting side-load on the bore. This causes transmission fluid pressure spikes and leads to various shift issues. Aftermarket kits with upgraded valve and sleeve assembly allow the bore to be refurbished.
- Leaking O-rings at various end plugs causes leaks inside corresponding circuits. The resulting pressure losses will impact the control of various components and cause shift issues. Renewing end plugs eliminates leaks and restores proper function.
Scions that use a 6-speed automatic transmission, either a U760E inside a second-generation Scion tC or an A960E found in Scion FR-S, can develop a noticeable grinding noise from the engine bay while driving. A mild vibration can sometimes accompany this.
The noise and vibration frequency will increase as the vehicle speeds up. In the initial phases, this will happen only when the vehicle is cold, but with time can become a constant issue.
Harsh 2-3 shifts
- Worn or damaged rear cover bearing, which happens as a result of high mileage or poor maintenance. Situations like transmission fluid low level or skipped fluid changes will cause overheating, which results in bearing damage or excessive wear. Replacing the bearing is the only solution.
Scion FR-S model that uses a 6-speed automatic transmission, designated as A960E, can have issues that affect 2-3 gear shifts. This will either be a delayed, harsh upshift on accelerations or a harsh downshift from 3th to 2nd gear while coasting. In some cases, there will be a surge in engine speed. If severe enough, this may trigger a check engine light.
- Excessive wear inside the lockup control valve obstructs its movement and causes the Torque Converter Clutch to remain applied during gear changes, resulting in harsh shifts. If there is a leak and resulting pressure loss, this will prevent TCC lockup and cause surges and fluctuations in engine speed. Installing an upgraded and oversized lockup control valve kit restores controlled operation.
Scion FR-S model that uses a 6-speed automatic transmission, designated as A960E, can have various issues ranging from shift flares to incorrect or harsh ones. Unlike TCC-related issues, this can affect all gears and lead to burnt clutches if driving like that for long.
Whining and rattling on acceleration
- Excessive brake control valve bore and bodywear cause pressure losses or cross leaks to adjacent hydraulic circuits and upset the delicate movement of the brake control valve. Refurbishing the bore and installing an oversized brake control valve kit will solve the issue.
Several Scion models have a Continuously Variable Transmission version, which has several different designations, all of which share the same issues. The most common one is a loud and severe whining noise while driving, which a loud acceleration can sometimes accompany. There will be no other symptoms.
- Failed primary or secondary pulley bearing is a well-known issue that affects these transmissions and causes rattle and whining noise. Whether the primary or secondary bearing is the issue involves a test drive. If the tone and pitch of the noise change during downshifts, the fault is with the primary pulley bearing. The secondary pulley bearing is a probable fault if a constant occurs during shifts. There are aftermarket upgraded bearings available on the market.
We hope you find the Scion Transmission Problems and Causes guide helpful. Check these troubleshooting and repair guides
for more help on your Scion.