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Big clunk when accelerating in a straight line

Hey Everybody!

I myself am not too familiar with car mechanics which is why I come to you for help. My brother is a mechanic and cannot seem to find the problem. A year ago, I purchased a 2010 Toyota Corolla LE from a dealership. Nothing stood out during the test drive. We were trying to push the car by speeding up really fast. It drove perfectly. After buying the car, I accelerated slowly while leaving the parking lot and was startled by huge clunk.

The Problem I now know when the clunk happens. When I accelerate in a straight line (slowly) the shift between 1st and 2nd causes a build up revving sound and then a big clunk which jolts the car. Keep in mind my car is an automatic. When the clunk hits, it almost feels like someone lightly rear-ended us. The first time I even looked back cause I thought I was hit. However, when I accelerate with a lot of gas, it seems to jump gears and it drives fine. The only problem is only ever with the change between 1st and 2nd gear.

Does anybody else have this problem or found a solution? I am wondering if I should just sell the car, put up with it, or take it to mechanic after mechanic looking to find the problem. Please help!

It souns like a transmission problem. May be low on fluid, may be in need of a fluid change, it may need a rebuilt transmission. The car needs service at a qualified shop.

So your brother is a mechanic? What does he say? He can experience for himself, we are just out here on the web with no contact with the car.

1 Like

Your 1 yr timeline seems odd.
How did you leave dealer lot slowly on test drive?
You didn’t?
Driven hard, it shifts ok?
Driven casually it has severe clunk?
How much has it been driven in last year?

My 2012 Corolla did that with worned stabilizer end links.It has nothing to do with the transmission.