Transmission clunk? Can anyone identify the problem please?

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Nov 9, 2006 | 08:08 PM
  #1  
Hey everyone,

I just put a new clutch in last weekend and everything has been great up until tonight. I went to taco bell for some dinner and when I left there I noticed a knocking ONLY on de-acceleration. It also knocks a little when I take off in 1st or slow shift gears. Under + acceleration there is no clunk, so Im kinda confused. It sounds like its coming from the driver side front wheel well, but that transmission is there also so Im not sure.

The noise is a constant clunk about half a second apart and it is speed dependant. Once again, only on de-acceleration. I noticed I have a split cv boot and have had it for about 2 months- I've neglected to fix it. Do you guys think its the cv joint or something in the tran? It has gl-4 85-90 gear oil.

Someone please shed some light, thanks.
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Nov 9, 2006 | 08:31 PM
  #2  
Does it sound like its coming from the axle, driverside??? Im kind of having the same problems. Hearing a clunking noise from it sounds like the axle. But I'm an auto..0_o?
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Nov 9, 2006 | 11:30 PM
  #3  
I am had that problem...now it's making noise troughout the speed. The axle is the problem....which explains the tear.

In my case, the motor mount is giving play to the movement of the engine...When I accelerate...the engine would play and the axle would bend along...causing the noise.

You might want to check the front (radiator) mount for cracks or wear.
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Nov 10, 2006 | 08:25 AM
  #4  
Yes I'll do that, thank you.

What troubles me is I have had bad halfshafts before, I dont get the clunk on any kind of turn or change in terrain- just on deacceleration when its in gear, in neutral its fine.
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Nov 10, 2006 | 12:59 PM
  #5  
update:

After driving it today I noticed that the clunk is now present under acceleration now. Still when I put it in neutral the clunk goes away, I even tried hard steering to see if it was the drive axle. Honostly, if it was the halfshaft wouldn't the clunk be constant? This makes me pray its not my transmission.

There is also a whine now when Im slowing down in gear. Its a high pitched whine that grows lower as the car slows down, Im pretty much clueless now. Can anyone offer advice?
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Nov 10, 2006 | 02:00 PM
  #6  
have you checked both motor mount? Since it's starting to sound during acceleration...you may want to check the rear motor mount also.

I fixed my clunking problem. Visually, I see a very fine crack, after removal of the mount, the mount was practically destroyed.

Good luck...You may need a partner to help out to see what the problem is. Raise the car at a safe level and inspect. Gotta be careful before you go under the car while it's running, any mistakes could cause you an arm, fingers,...etc.
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Nov 10, 2006 | 06:04 PM
  #7  
well., my car still clank, but not as loud as before. Maybe a transmission mount needs to be changed. I'll do that next week. GL
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Nov 14, 2006 | 02:20 PM
  #8  
Ahhhhh, the beauty of the search feature. I'm having a similar problem. My girlfriend seems to think its the axle as she has had the problem before. My noise is coming from the driver side wheel area(it seems). One Nissan dealership diagnosed it as a bad axle, another dealership said it was a bad rotor/pad. I got the rotors and pads replaced today and the problem is still there.

For me the problem occurs during acceleration to about approx. 40mph. At 40, I can let off the gas, accelerate again, and recreate the noise/clunking at will. I go back to the dealer tomorrow.
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Nov 14, 2006 | 03:00 PM
  #9  
Turns out my problem was internal. Now the car is stuck in what seems to be neutral, yet when I let the clutch out it lurches. Very interested.
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Nov 14, 2006 | 03:27 PM
  #10  
I'm guessing you have some chipped gears. Sometimes there is enough bearing damage that the shafts aren't held solidly, and this leads the gear teeth to chips only at the teeth tips. Then they'll make noise, especially on coasting, where there isn't much load on them and the excess backlash allows the teeth to bounce back and forth against each other.

The shifting trouble is most likely due to stuff falling down into the shifter area of the tranny and jamming it. Even steel parts will collect there if the magnet is already gunked with metal debris.

Sorry, that's not good news. But it's what i would bet is going on. Drain the tranny oil and see. This is one situation where I suggest carefully removing the position sensor for the drain/inspect.

Dave
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Nov 15, 2006 | 07:59 PM
  #11  
I have an issue with my cars tranny, and i come across a post on nico, basically if you are having any kind of noise while shifting, its pobably because transmission is not certain what gear it should go to.

Transmission has two input sources one is Vehicle Speed Sensor (primary) and other is TPS (backup). If one of them is not working properly transmission tries to shift to other.
Easiest way is to plug out VSS and see how your car drive if after plugging out tps car runs fine your issue is VSS.

Try it before opening transmission,
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May 17, 2007 | 09:29 PM
  #12  
Quote: Hey everyone,

I just put a new clutch in last weekend and everything has been great up until tonight. I went to taco bell for some dinner and when I left there I noticed a knocking ONLY on de-acceleration. It also knocks a little when I take off in 1st or slow shift gears. Under + acceleration there is no clunk, so Im kinda confused. It sounds like its coming from the driver side front wheel well, but that transmission is there also so Im not sure.

The noise is a constant clunk about half a second apart and it is speed dependant. Once again, only on de-acceleration. I noticed I have a split cv boot and have had it for about 2 months- I've neglected to fix it. Do you guys think its the cv joint or something in the tran? It has gl-4 85-90 gear oil.

Someone please shed some light, thanks.
Were you able to isolate the problem? I'm having the same problem with my brother's car after I missed a 1-2 shift. I'm afraid I chipped some gears.
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