Solenoid C

[UberRoo]

Originally Posted by tomssvx

get it in the air before anyone gets anymore ideas.

Too late.

The speed sensor for the rear wheels, which detects speed differential between the front and rear wheels, is located in the transfer housing. I believe it's some sort of hall-effect sensor, but I'm not really sure. Anyway, it's magnetic and it picks up junk that may be floating around in your transfer housing. I wonder that if something was broken, if it might be stuck to the magnetic sensor and be preventing it from functioning properly.

There is some sort of mechanism in the transfer housing that I think is part of the parking pawl assembly. (I could be wrong, but it’s in the right place and I seem to recall seeing that in a diagram somewhere.) Anyway, it occurred to me that it might be possible that something has come loose and is rubbing against the clutch basket. ...or not. Just speculating. The circumstances of when and how this symptom began would suggest that something suddenly broke. Though a little far-fetched, this concocted scenario would explain it.

Still, be sure of where the noise is coming from before you go wild tearing the transfer housing apart.

Also, it sounds like solenoid 'C' is functioning just fine. The problem appears to be that it's getting a bad signal from the TCU. Have you pulled codes? If not, do so. If you have, what are they?

[AvPPoW]

I was pulling a code 24, went back out there today, no exisiting code. If I look under previous codes it shows me code 24

[Earthworm]

Sounds like you have the same issue UberRoo has. I'm betting the wire is broken.

[dromano]

Originally Posted by svx_commuter

I did this work on my SVX about 4 years and 120k miles ago. Mine was stuck so that there was no RWD.

You have to take down the exhaust so you need the exhaust gaskets and springs and bolts and nuts. I replaced all five gaskets so that there would be less chance of a leak afterwards. The spring bolts had to be cut out with a saws all.

I used a new plate and gasket for both sides because I do not like to spend time cleaning old gaskets off if I can avoid it.

You will need the gasket between the transfer housing and the tranny.

There are more searchable posts on this subject.

Good to see you are still posting. I've been away for awhile.

[AvPPoW]

Car is on jackstands and bottom of car is stripped. Have a clear view of the rear end of the tranny, will investigate more tomorrow.

[UberRoo]

Since you have to remove it anyway to look inside the transfer housing, pull the speed sensor first. Mine had metal debris on it when my transfer clutch basket failed. I suspect yours might too, but from the parking pawl instead. (Just a theory.)

Speed sensor: Located on the transfer housing, passenger's side near the top. Should be the only 10mm screw back there.

[AvPPoW]

Ok, what the hell. Used a mechanics stethiscope, and the noise is DEFINATELY coming from the transfer housing, no noise from the front diff. Drained the oil, no metal bits. Took the speed sensor out (^thanks for the tip), no metal bits. Took the transfer housing off, inside is immaculate. The wire to solinoid c is intact, and the bearings all look and seem to spin fine. I put 12v to the solinoid and it clicks, seems to be working. I'm friggin stumped. Tranny filter? Rear diff (need to check it, looks nasty)? I'll get some pics of inside. Anyone have any other ideas

[UberRoo]

Hmmm... That's entirely odd that nothing apparent seems awry. How did you test with the mechanic's stethoscope? With the engine running? Turning parts by hand? What was turning during your test?

Now that everything's apart, I would turn the parts by hand and listen again. At this point you've isolated the sound to somewhere in or near the rear of the transmission. It's a terrible handicap for us to speculate on the problem when we don't have firsthand experience of what the noise sounds like. In any case, sound can definitely travel quite a distance though something, but now that some of the parts have been removed or separated, I would try to reproduce the sound again to further isolate it. If you just start removing parts until the sound stops, you'll know the last part you removed was the culprit, or at least a component of the problem.

This little mystery has me intrigued.

[AvPPoW]

Pictures are here:

http://pg.photos.yahoo.com/ph/avppow/album?.dir=/3e59

I used the mechanics stethiscope when the car was running at about 40 and let off the gas. It doesn't make the noise otherwise. If the parts are turned by hand, it all sounds fine. Everything is clean, I just dont understand whats causing the noise.

[SVXRide]

Sounds like (no pun intended) you've got some longitudinal slop -- when you let off the gas you're "unloading" the drivetrain, thus the noise goes away. Have you pulled the clutch pack out to see if there is any "slop" in the assembly?
-Bill

[UberRoo]

Not being able to reproduce the sound by hand really complicates things. As SVXRide suggests, I think you should carefully inspect the transfer clutch. I doubt there is anything wrong with it, but it would be prudent to make sure. Aside from that, as nothing in the transfer housing looks out of order, I think I'd give it a clean bill of health. I believe you when you say the sound definitely seems to be coming from the transfer housing, but I'm not confident that it really is. As I mentioned before, sound will travel through things. It could very well be traveling from your front or rear differential all the way through the driveshafts. Judging by the fresh-looking oil on the rear differential, I would start there. Since you said you were traveling at about 40mph when you were trying to locate the sound, that really makes it hard to crawl under the car and pinpoint every possible source. I gather that you were not able to listen to the rear differential, center driveshaft bearing, or wheel bearings while doing this?

When or if you decide to look at the transfer clutch, here's a tip: The two big gears inside the transfer housing are matched gears. There are supposed to be alignment marks on them, but I was never able to find any on mine. If you take out the transfer clutch, you may have to pull the upper gear out with it. You shouldn't have to, but sometimes the clutch packs don't come apart very easily. If you do remove it, before you do, mark the gears so you can align them again. A paint pen works well for this.

Since it seems that you've probably eliminated anything inside the transfer housing as a problem, perhaps the next possible step would be to isolate the rear differential. I would do this by removing the rear section of the driveshaft and driving around.

[TomsSVX]

Originally Posted by SVXRide

Sounds like (no pun intended) you've got some longitudinal slop -- when you let off the gas you're "unloading" the drivetrain, thus the noise goes away. Have you pulled the clutch pack out to see if there is any "slop" in the assembly?
-Bill

The noise starts when the accelerator is no longer depressed. When he is coasting the sound occurs

Tom

[SVXRide]

Originally Posted by tomssvx

The noise starts when the accelerator is no longer depressed. When he is coasting the sound occurs

Tom

My thought still holds -- with the accelerator pressed down he's loading up the drivetrain, thus closing up any "slop" (thus no noise) - letting off the gas and the loading is released, thus allowing things to make noise...
I agree with UberRoo in that it may actually be noise translating up from the rear diff and/or driveshaft.
Can you disconnect the driveshaft and run the car up in rpms to see if you still get the sound at the transfer case?
-Bill

[AvPPoW]

Originally Posted by SVXRide

Sounds like (no pun intended) you've got some longitudinal slop -- when you let off the gas you're "unloading" the drivetrain, thus the noise goes away. Have you pulled the clutch pack out to see if there is any "slop" in the assembly?
-Bill

To clarify, the noise occurs when I let off the accelerator

Originally Posted by UberRoo

Not being able to reproduce the sound by hand really complicates things. As SVXRide suggests, I think you should carefully inspect the transfer clutch. I doubt there is anything wrong with it, but it would be prudent to make sure. Aside from that, as nothing in the transfer housing looks out of order, I think I'd give it a clean bill of health. I believe you when you say the sound definitely seems to be coming from the transfer housing, but I'm not confident that it really is. As I mentioned before, sound will travel through things. It could very well be traveling from your front or rear differential all the way through the driveshafts. Judging by the fresh-looking oil on the rear differential, I would start there. Since you said you were traveling at about 40mph when you were trying to locate the sound, that really makes it hard to crawl under the car and pinpoint every possible source. I gather that you were not able to listen to the rear differential, center driveshaft bearing, or wheel bearings while doing this?

When or if you decide to look at the transfer clutch, here's a tip: The two big gears inside the transfer housing are matched gears. There are supposed to be alignment marks on them, but I was never able to find any on mine. If you take out the transfer clutch, you may have to pull the upper gear out with it. You shouldn't have to, but sometimes the clutch packs don't come apart very easily. If you do remove it, before you do, mark the gears so you can align them again. A paint pen works well for this.

Since it seems that you've probably eliminated anything inside the transfer housing as a problem, perhaps the next possible step would be to isolate the rear differential. I would do this by removing the rear section of the driveshaft and driving around.

I was not travelling at 40mph, the car was on jackstands and my dad was in the drivers seat. I was under it with the mechanics stethiscope. The sound is NOT from the front diff, as I touched it and it was alot weaker than when I listened to the back of the transfer clutch housing. I couldn't check the driveshaft (cause it was spinning) and didn't think of checking my diff. Tom (SVXFiles) had me mess around with my rear diff and it didn't seem too bad. I'm 99.9% sure whatever the noise is it's coming from the transfer clutch pack. If someone has basic steps torward removing the clutch pack and inspecting it, please post. I wiggled it a bit and it didn't want to come out, so I didnt want to mess with it/screw it up.

Originally Posted by tomssvx

The noise starts when the accelerator is no longer depressed. When he is coasting the sound occurs

Tom

you gotta get down here to look at it, I'm so confused

Originally Posted by SVXRide

My thought still holds -- with the accelerator pressed down he's loading up the drivetrain, thus closing up any "slop" (thus no noise) - letting off the gas and the loading is released, thus allowing things to make noise...
I agree with UberRoo in that it may actually be noise translating up from the rear diff and/or driveshaft.
Can you disconnect the driveshaft and run the car up in rpms to see if you still get the sound at the transfer case?
-Bill

Driveshaft is disconnected but car cannot be run that way, as ATF is fed to the splines on the driveshaft and without it there oil would shoot out

[TomsSVX]

I was just at his house and I believe we found where his problems lie. The clutch pack seems in ok shape minus the few teeth inside that look to be chipped. The outter edges of his basket are serated also. This is where I believe he is getting his binding problem. The clutch disks slip into the NON-stock grooves and are not abe to be released. His noise may also be comming from this. He does however have 1 universal joint failing. Thats my story and I'm stickin to it. John, get some pics up of the inner basket to show them what I mean

Tom