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K

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hi i hav a 1997 rav4 automatic 4wd. At high speeds when i begin to decelerate i am hearing a loud thump coming from i think the diff. can anyone help?
 
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Discussion Starter #2
kc8319,
Does this sound happen at any other time than when you decelerate? What speeds are you talking here?
My initial thoughts are that either your exhaust is banging around, or some other bushing or hanger is cracked or loose...

Bogatyr
 

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Could be caused by a bad U-joint possibly. I am assuming that your torque converter is locking and unlocking properly. It was within the rear differential itself I would expect a whine or groan. Like the other poster suggested I would make sure all your mounts and exhaust hangers are good.
 
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Discussion Starter #4
Thanks . i have a feeling it could be torque converter since at times i would hear it when i further accelerate when i am going at approx 85km. what do u think?
 
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Discussion Starter #5
It's difficult to comment on a thump without hearing it - but, mine does something similair and I think it is going to be simply play in the transmission that knocks when you lift off.

At the speed it does it at you acceleratle and lift off jerkily you can produce the noise - it comes from under the driver seat (Passenger for LHD)
 
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Discussion Starter #6
kc8319 said:
hi i hav a 1997 RAV4 automatic 4wd. At high speeds when i begin to decelerate i am hearing a loud thump coming from i think the diff. can anyone help?

Yes, this is due to the slack between the propeller shaft and the rear differential. It is normal.

If the noise comes while you accelerate quickly then you have to replace the shimms in the rear differential which will reduce the noise. You could also check and replace the differential mount. I did both and the noise has reduced a lot.
 
K

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Discussion Starter #7
Thanks u guys, i am having it check out this week, i will let u all know what it was. I just hoping it is not the tranny acting up.
 
K

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Discussion Starter #8
Normal. I have this too on my Manual. Never found out what the problem was. Happens when I have a new clutch in it. After the clutch spring wear in a bit, the thumping is gone.
 
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kidong said:
Normal. I have this too on my Manual. Never found out what the problem was. Happens when I have a new clutch in it. After the clutch spring wear in a bit, the thumping is gone.
Hey Guys,

Is there anyway we can ask Toyota about this ?
 
J

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Discussion Starter #10
Hello - first post here -

I know a few RAV 4 owners who have what is probably the same transmission 'clunk'. I was suprised to find relatively little on this 'problem', or at least that owners had linked to being related to the same underlying issue.

What I have heard of from several owners is of a 'grabbing clunk', first noticed on manual cars if you change gear untidily. It appears to happen during the transission from forward loading to backwards loading on the transmission. This is quite different from regular transmission backlash. It's more than a clunk, and more like a clutch or transmission component grabbing for a second or two under certain load conditions.

I have a 1995 RAV4, which until recently has had very little of this problem evident, but it has always been present to some extent, since the vehicle was brand new. During the past year, what sounds like the same noise (from the rear transmission) has got much worse, and instead of being just one CLUNK, it is now several clunks of decreasing volume. This happens without changing gear, and every time the vehicle goes from engine braking (decelerating) to accelerating. The harder the change in acceleration, the louder the sequence of Clunks.

At the moment (from reading other posts and talking to a local Toyota dealer) I think it could be transmission mounts that need replacing. There must be RAV4 owners who have gone through this process. Can anyone confirm their experiences?

Also, anyone know of good, cheap parts suppliers for Toyota spares in the UK?

Thanks, Jon.
 
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Discussion Starter #11
Just in case anyone else stumbles across this old thread like I did, Here is my update:

I put the car up on a lift and pulled around various rear drive components. At first, everything looked sound. The drive shaft was solid, so were its drive couplings. Then I tried lifting the rear diff. housing, and it went up 1" to 2" without much effort. Then it was easy to see that the rubber in the rear mounting was totally split. I haven't replaced the part yet, but that's got to be the problem.

My guess is that something in the way the torque coupler for the rear drive works, tends to put sudden quite harsh loads through the rear transmission, and hence tends to pull hard on the diff. mounts.

The new mount is going to cost something like £60, and if it doesn't fix the problem, I will post the outcome here.
 
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Discussion Starter #12
transmission clunck

I'd be interested in what you find.

I get that clunk when the engine is cold and RPM's high at the 1-2 shift. Seems to occur in cold weather only. I've assumed it was simply parts of the all-wheel drive system "settling in" as they warmed up, but maybe not. I have 90k miles.

I guess I am not a "tidy" shifter either. For all it's good points the Rav's shift points have never particularly suited me or the terrain I travel. I always want it to get about it's business faster than it wants.
 

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JonD said:
My guess is that something in the way the torque coupler for the rear drive works, tends to put sudden quite harsh loads through the rear transmission, and hence tends to pull hard on the diff. mounts.
1st gear will create lots of TORQUE... and when you are stationary and put all the torque down to get moving, it ends up twisting the diff in its mount...
 
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Discussion Starter #14
occurs on mine also .. most noticably when slowing down from high speeds .
 
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Mine too

I have this sound also from my Manual. I figured it was normal.
 

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check ur differential support, there are 2 front and rear, the front support is quite hiiden bec it is in between the fuel tank and, you have to inspect id by hand 2 chk it out, i replaced mine after that the noise was gone
 
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Discussion Starter #19
I have the same loud clunk when shifting or taping the pedal, just bought the car
142k on it the guy drove in stop an go traffic and its a awd 5speed 2 door.. I thought it was the spider gear in the rear diff , everything fills pretty tight in the driveline
I will check out all the mounts on the diff for problems I hope I find something wrong with it, not sure how much longer I can live with that noise
 

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I looked at my driveline, as there seems to be a clunk at times when things are loaded heavy (lots of throttle on/off).
I can say my differential mounts are intact, but the differential is mounted softly,
the rear differential rear mount is very soft, and I can see things moving around
quite a bit under heavy loads on the driveline.

I did not get a good look at the transmission/front diff mounts, but I know from an old camry we had the motor mounts can break and you cant see it, or tell, without
removing them.

On that car, the tourque arm rubber was totaly gone, and when I replaced the front motor mount, I found it just flopping around and in 2 pieces!
You cant see that with the cover on and the motor weight on it.

When I did the timing belt on the rav, the side motor mount was fine, I have not checked the others, but i dont think anything is bad, its just the soft suspended parts to keep the noise down.


Brett
 
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