# click/clunk noise



## sent07 (Oct 1, 2010)

Hi. I have a 2007 Sentra CVT tansmission with about 33k. It has had a clicking sound when shifting from drive<>reverse for a while however recently has become louder, making a clunk sound. It always happens when shifting drive<>reverse. It has also started making the sound occasionally when stopping/accelerating. It has a rebuilt title so the warranty is void but had no front damage.

I have read about several different things that could possibly make this sound. I thought maybe an inner cv joint but they seem tight. There is no problems with the cv joint boots, no fluid leaks anywhere. There is a little play in the inner CV joint where it goes into the transmission, but less than 1/8" I would say. I also read about bad motor mounts and hoped this was the problem, but they "look" ok. Seems as if there are 3 of them. And lastly could this be the CVT transmission? It works fine and makes no sound when driving. The fluid seems to be clean. What usually goes bad in these?

Any ideas or suggestions would be appreciated before I take it in to a garage. Thanks in advance.


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## ChrisAce (Sep 30, 2004)

I recently purchased a 2010 Sentra so I am not too familiar with the CVT operation. But I know I like it!

Have you checked the fluid level lately? Also, not sure what the recommended mileage to flushing the fluid is. For standard automatic transmissions I have seen shifting clunks usually fixed by a nice clean fluid flush.

Good luck! Be sure to let us know what you find out.


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## sent07 (Oct 1, 2010)

I took it to the local transmission shop today. He's pretty sure it is the left axle outer cv joint however said it is definitely unusual considering the boot is excellent and there is no popping with wheel cut driving in a circle. 

I ordered one today and it will be in next week sometime. I'll repost with the results when I get it in.


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## ChrisAce (Sep 30, 2004)

So I should learn to do my homework before making suggestions. I was checking out the design of the CVT and it doesn't use clutches, which means there are no solenoids that route fluid through ports. It is simply a pulley that changes in width causing the belt to ride up or down making the turn ratio change, thus making the wheel rotation speed go up or down.

I know that they started with the CVT on the Altima near the beginning of this century so you may want to check that forum to see if they have similar symptoms, assuming of course this ends up being CVT related.

I hope it is as simple as a drive shaft. But then again that means I may have this problem. 

On a side note, I can fell a slight thump when changing from P to R to D or visa versa, but I have to assume it is normal since I am not familiar with the CVT. Mine only has 500 miles on it.


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## ChrisAce (Sep 30, 2004)

I found this article about the common thump sound it makes while shifting. Now I am convinced, though your problem seems to be more substantial.


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