4.44 Swap Finished; Complete with horrible problematic sound

[Dynamic Entry]

92 SVX has been in the air for 8 weeks or so. Have been relying on SVXFiles posts, pms, and the generally helpful members on this forum.

Everything is finally "done", but the car is making a loud metallic rattle/rubbing noise that cannot be ignored. So I have not lowered it back to the ground.

Here is a video of the noise, but it was taken on my phone and so it does not really sound the same as in person. The sound in the video has a lot of bass, but in person the noise does not sound like burble, it is a grating noise.

The most important part of the video is to notice that the noise is engine speed related, and that somehow it briefly disappears when moving from Park to Reverse.

I know that asking for help to diagnose a sound might be futile.

Here are relevant notes for the motivated reader:
- torque converter was fully seated as best I understand it
- am using BG products synth atf, and put some in the TC before seating
- final touches were to get the exhaust back on (I sheared a stud on the header and so this took me a while) and to fill with ATF.
- needed engine running to check ATF level, decided it would be fun to start it with open headers
- engine fired up pretty easily, and went into a stable high idle. It was gnarly loud
- was encouraged because with wheels in the air I could select all gears forward and reverse and everything was spinning nicely
- proceeded to put the exhaust on (this took me more than one day because I ended up needing to buy new cobalt bits to drill out the sheared off stud)
- used all old exhaust gaskets, to see if I could get away with it (I took exhaust off at headers and muffler and left everything else between connected)
- only exhaust leak was at the header outlet flange where I drilled the stud out
- engine/exhaust pretty quiet now, so I noticed a loud noise that I assumed was coming from heat shield or leaky exhaust connection
- with engine running I put pressure on remaining heat shields and exhaust joints, but noise was not affected
- became afraid that noise was coming from inside the engine/transmission somewhere
- wondered if I did something wrong with torque converter or if my donor 4.44 is messed up
- took exhaust back off and listened to it run with open headers again
- noticed that the same noise was there, just harder to notice over open exhaust racket
- sounds like metallic rubbing, engine speed dependent
- put exhaust back on, including copper RTV to fix leak at drivers side header outlet
- now exhaust is very quiet and no leaks, but the problem noise is more noticeable and more scary

[Dynamic Entry]

I found a thread on another forum that addresses my exact situation.
http://www.ultimatesubaru.org/forum/...rter-properly/

This description from the above thread describes the sound and variation that occurs when shifting just like what I am experiencing:
"[when] it's well below 0F air temp then it does it for a minute or two at idle in park. Then, with my foot on the brake, i can move the shifter slowly through the gears (change gear every 5 seconds) and the noise is present once the vehicle has changed gears, but goes away during the shifting of gears. The difference in noise between D and the other forward gears is minimal, but the biggest change is from R to a forward gear, or to/from neutral. When cold, the noise is most audible with a stethescope pointed on the bell housing."

There is some speculation that it might be a cracked flexplate. I did look at the flexplate when I had the transmission down, and I did not see any damage. Perhaps I need to check the torque and condition of the flexplate to TC bolts.

I will pull the inspection cover and see what I can see...

BTW - The thread also discusses the ins and outs of torque converter seating, and it confirms my belief that I did it correctly.

[elninoalex]

<<<There is some speculation that it might be a cracked flexplate. I did look at the flexplate when I had the transmission down, and I did not see any damage. Perhaps I need to check the torque and condition of the flexplate to TC bolts.

I will pull the inspection cover and see what I can see...>>>



It seems to me that you are looking in the correct place. FP or TC or bolts. I just had an Impreza with a bad bearing in the TC that sounded similar to that.

[svxfiles]

I just heard of this thread, and listened to the video.
The (what I would call a) scraping sound,
it is always there when the engine is running?

[svxfiles]

elninoalex,
it's 3:33 in the morning!@
Don't you have school tomorrow?!

[elninoalex]

Nah Dad, I'm on the West Coast.

[Dynamic Entry]

Thanks for the late-night vigilance gentlemen!


Yes, the noise is constant at idle, and with revs in gear (without load since wheels are still not on ground)

But, the noise disappears completely for just a moment when shifting from Park to Reverse.

And, to clarify, these noises were not present before the swap.

I re-used the SVX torque converter and re-used the 4 old TC bolts.

[SVXRide]

Get yourself an engine stethiscope (sp?) or a very long screwdriver and put it in contact with the bell housing (front diff housing) and then back on the rear diff. This will help you isolate where the sound is coming from.

You won't be able to see a cracked flexplate unless you remove the trans. The cracks propagate from bolt hole to bolt hole where the end of the crank butts snugs against the flex plate.

Bill

[svxfiles]

From the video it seems like the noise is coming from a rotating part.
Is it possible that from a bolt dropped into the bell housing TQ bolt access hole?
Other than the flexplate, the torque converter and the front pump, nothing inside the reansmission should be rotating when in park.
Is the starter some getting spun by the ring gear on the TQ?
That could make a similar noise.
If you can not find an external noise source, then you just have to pull the transmission out again and re check everything.

[dannmarr]

Originally Posted by SVXRide

You won't be able to see a cracked flexplate unless you remove the trans.
Bill

My Mechanic was able to see my cracked flexplate with an inspection camera.

[svxfiles]

I have never seen an SVX with a cracked flexplate
that you could see the cracks,
without removing the torque converter,
the crankshaft bolts and
the cover plate.

Go to my locker and look up;
Amazon Parrot's TQ+flex plate
BTW, Picture #21 shows the TQ fully seated.

[Dynamic Entry]

Originally Posted by SVXRide

Get yourself an engine stethiscope (sp?) or a very long screwdriver and put it in contact with the bell housing (front diff housing) and then back on the rear diff. This will help you isolate where the sound is coming from.
Bill

I will try to pin down exactly where the noise is coming from.

Originally Posted by SVXRide

You won't be able to see a cracked flexplate unless you remove the trans. The cracks propagate from bolt hole to bolt hole where the end of the crank butts snugs against the flex plate.

Originally Posted by svxfiles

I have never seen an SVX with a cracked flexplate
that you could see the cracks,
without removing the torque converter,
the crankshaft bolts and
the cover plate.

I didn't think to remove the cover to examine the flexplate. But I also had no previous reason to...

Originally Posted by svxfiles

From the video it seems like the noise is coming from a rotating part.
Is it possible that from a bolt dropped into the bell housing TQ bolt access hole?
Other than the flexplate, the torque converter and the front pump, nothing inside the reansmission should be rotating when in park.
Is the starter some getting spun by the ring gear on the TQ?
That could make a similar noise.

It is possible that something dropped in through the access hole, yes. But I would think that something loose might become dislodged, whereas this noise is very consistent.

I will try to see if the noise is coming fro the starter. How might this occur and how can it be avoided/prevented?

[svxfiles]

"I will try to see if the noise is coming fro the starter.
How might this occur and how can it be avoided/prevented?"


If a starter is incorrectly installed, (at a slight angle, etc.)
if the starter drive goes bad due to wear,
if the bell housing is not completely flush due to too many,
or not enough locating pins,
if the bellhousing is not flush due to a ground wire getting the way of the seating surfaces,
all can cause a problem.

[Hocrest]

With the engine off, can you hear the noise by turning the engine manually? If so, remove the starter and try again to turn it manually.

[dannmarr]

Originally Posted by svxfiles

I have never seen an SVX with a cracked flexplate
that you could see the cracks,
without removing the torque converter

I was with my mechanic while he was using the camera. When he spotted the crack, he showed it to me. It wasn't the normal crack between the bolts, it was from the bolt to the outer ridge of the flex plate.