Grinding sound

[manofmayo]

I'm almost afraid to know what this might be.

Thursday afternoon I was coming home and I had switched into power mode, in 2nd gear, the tach was around 6300 rpms, when suddenly I heard a grinding noise coming from the front of the car. It lasted maybe 1/3 of a second. Immediately I let up on the gas and drove it home gingerly. Later I smelled all the fluids, but there was no burning smell anywhere. Also there was no drips anywhere under the car.

All Friday, I drove the car normally and I got no strange sounds.

Then tonight on the way home from Earl's, I accelerated onto the highway, again in power mode and in 2nd gear, and the tach reached 6300 rpms, I briefly heard the grinding sound again.
I haven't checked anything yet, but the car drives fine and the transmission shifts as good as when I bought it 6 months ago.

Any ideas?

[lee]

Is this a new problem, i.e., you've done this before with no sounds?

I'd try revving it up in the garage. That might help narrow down the possibilities - if the sound is there then it's likely engine, flex-plate or torque converter as not much else will be moving.

[manofmayo]

Never had the problem before. Isn't it strange.

Also, I think the first time it did it, I must have been in 1st, not 2nd, I don't think I was travelling that fast.

I've tried to repeat the problem in my driveway and on the highway and not had any luck.

Is there an easy way to check the flex plate or torque converter, or does it require pulling the tranny?

Thanks

I've had that sound at that exact RPM range on both of my SVXs. Both were FWD. The first one had the original tranny, and even at 98k miles, there was no slip in shifting. My current one has 135k miles, a rebuilt tranny with 20k on it, and it also makes the noise (but less often than the last one). Has no slip in shifting, but there is some serious weight movement when it shifts from 1 - 2 between 1.5k and 2.5k RPM.

Neither tranny seemed to ever get worse in the noise or in shifting. I still don't know what causes it, but maybe that'll make you feel a bit better.

[manofmayo]

Originally posted by deruvian
I've had that sound at that exact RPM range on both of my SVXs. Both were FWD. The first one had the original tranny, and even at 98k miles, there was no slip in shifting. My current one has 135k miles, a rebuilt tranny with 20k on it, and it also makes the noise (but less often than the last one). Has no slip in shifting, but there is some serious weight movement when it shifts from 1 - 2 between 1.5k and 2.5k RPM.

Neither tranny seemed to ever get worse in the noise or in shifting. I still don't know what causes it, but maybe that'll make you feel a bit better.

Yes, it does make me feel better. What do you mean by serious weight movement? When accelerating hard, do you lift off the throttle before redline to make sure this doesn't happen? How much dies this happen to you? According to my mechanic, my tranny was rebuilt at 90k and I have 157k on it now, and my tranny has always seemed strong.

Originally posted by manofmayo


Yes, it does make me feel better. What do you mean by serious weight movement?

By serious weight movement, I mean it seems as though one of my transmission mounts may have a problem. When it shifts from 1 - 2 in the 1.5k - 2.5k RPM range, I get a "clunk clunk" if I don't back off the throttle. The only problem is, I don't know how to "check" a mount, as people keep telling me to do.

When accelerating hard, do you lift off the throttle before redline to make sure this doesn't happen?

The "clunk clunk" doesn't happen at redline. Only between 1.5k and 2.5k on the tach.

How much dies this happen to you?

Pretty much every time it shifts from 1 - 2 in that range.

According to my mechanic, my tranny was rebuilt at 90k and I have 157k on it now, and my tranny has always seemed strong.

It looks like we're in the same boat with that one. My tranny seems to be working well, but occasionally makes that grinding noise at very high RPMs, just before shifting.

[TomsSVX]

my fwd does that same clunk cunk sound when it shifts 1-2. What the heck is that, it sounds horrible and i just it to go away, i am putting a new mount in it this weekend, ill let u know.

Originally posted by tomssvx
my fwd does that same clunk cunk sound when it shifts 1-2. What the heck is that, it sounds horrible and i just it to go away, i am putting a new mount in it this weekend, ill let u know.

AWESOME!!! Thanks man. Be sure to keep me posted. I want the damn thing to go away too.

[manofmayo]

The problem had been growing worse, I couldn't rev the engine about 5k without hearing that sound.

Replace the knock sensors last week, now the grinding sound is gone.

[Bxsvx]

the sound is gone from changing the knock sensors? how is it related?

[TomsSVX]

It's an SVX, don't ask silly questions.

Tom

[Bxsvx]

lol I must knooooooooooooooooo the magic of the svx

[oab_au]

Originally Posted by Bxsvx

lol I must knooooooooooooooooo the magic of the svx

If the knock sensors were not working, it may have been knocking. Do you run preimum fuel?
Harvey.

[Bxsvx]

Yes, always. It happens sometimes. Sometimes the car will be so smooth, and then sometimes it will make grinding sounds. all the fluids are fine and dont smell bad, my tranny fluid is foamy though. I am going to change the fluid out, and see what happens

[Bxsvx]

update, I noticed when the car is cold it doesnt make a grinding sound, and the car runs real smooth and shifts excellent. Can the knock sensors retard timing and cause the sound?