I have a 2002 UZJ100, 2UZ-FE 4.7 V8, A343F / 30-43LE, with about 280,000 miles.
The original engine had misfires and low compression in several cylinders. After disassembly, significant cylinder head damage was found, so the engine was replaced with another 2UZ-FE. The original flexplate was reused.
Before the engine replacement, the vehicle was test-driven. Despite the engine problems, the transmission shifted normally and there was no drivetrain vibration.
After the replacement engine was installed, the vehicle initially drove normally for over 60 miles, then developed a strong vibration under acceleration. Later, the transmission also developed a 1–2 shift problem/slip and occasional metallic noise.
The transmission was then professionally rebuilt, including friction plates, seals, hydraulic work and torque converter rebuild. After reinstalling it, the vehicle drove normally for about 20 miles, then the same vibration returned.
Both driveshafts have been rebuilt. The front driveshaft was removed and the vehicle was tested with the center differential locked and rear-wheel drive only — no change in the main vibration.
Engine mounts were checked and one was replaced. Torque converter bolts were also removed, inspected and reinstalled — again, no change.
The transmission rebuilder has test-driven the vehicle and believes the problem is most likely transmission-related.
My main questions:
The original engine had misfires and low compression in several cylinders. After disassembly, significant cylinder head damage was found, so the engine was replaced with another 2UZ-FE. The original flexplate was reused.
Before the engine replacement, the vehicle was test-driven. Despite the engine problems, the transmission shifted normally and there was no drivetrain vibration.
After the replacement engine was installed, the vehicle initially drove normally for over 60 miles, then developed a strong vibration under acceleration. Later, the transmission also developed a 1–2 shift problem/slip and occasional metallic noise.
The transmission was then professionally rebuilt, including friction plates, seals, hydraulic work and torque converter rebuild. After reinstalling it, the vehicle drove normally for about 20 miles, then the same vibration returned.
Current symptoms
- Strong vibration under load, mainly around 1,200–2,000 rpm.
- If load is maintained around 2,000 rpm, the vibration continues.
- With very gentle acceleration, vibration is minimal or almost absent.
- Same behavior when starting in D, L or 2.
- No vibration in Reverse, even under stronger acceleration.
- Vibration disappears after shifting into higher gears.
- ATF level is correct; temperature was about 180°F when checked.
- ECU/TCM reset made no difference.
Both driveshafts have been rebuilt. The front driveshaft was removed and the vehicle was tested with the center differential locked and rear-wheel drive only — no change in the main vibration.
Engine mounts were checked and one was replaced. Torque converter bolts were also removed, inspected and reinstalled — again, no change.
The transmission rebuilder has test-driven the vehicle and believes the problem is most likely transmission-related.
My main questions:
- What could cause a load-dependent vibration in the lower forward ranges, but not in Reverse, and disappear in higher gears?
- Could a valve-body, pressure-control or solenoid problem cause a sustained vibration/shudder like this?
- Could an electrical connection, internal harness or ground problem cause this?
- Has anyone seen a similar A343F problem?