2000 Lexus RX 300 • 4WD Automatic • 120,000 miles

2000 Lexus rx 300 has grinding noise while I drive on the first gear (less than 10 miles/hr). As soon as the gear is automatically shifted to 2nd, 3rd, and so on, the grinding noise disappears.
The same noise can be reproduced if I drive on "L" clutch, then if I change the clutch to "2" it disappears. I showed to the mechanics, and they confirmed it is not due to breaks, wheel bearings, etc. IT could be due to transmission or engine. How can it be fixed. If I change transmission fluid, will the noise disappear?

January 15, 2011.

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