AWD Binding

TomsSVX · #1 04-16-2006, 08:29 PM

Yeah... turning up a code 24 out of the teal. I tried plugging in the FWD fuse and to no avail. Nothing happens??

Got a feeling it has to do with the chasis rather than the trans because I rebuilt the transfer clutches and solenoid C with parts known to be good but not new parts. This car has been having trouble with binding since before I got it. people like to just remove the rear half of driveshafts in order to "fix" their problems

Anyway, anyone have any ideas on where I should start looking before I go and buy a new solenoid C and tear the trans apart again??

Tom

Tim · #2 04-16-2006, 08:44 PM

My old tranny is cursed I tell ya! J/k

Bump for good luck

TomsSVX · #3 04-16-2006, 08:50 PM

well at least the AWD is working

Did u ever try to FWD fuse in ur car to see if it would do anything?? Just curios as to whether I am tracing wires in the car or the tranny??

Tom

oab_au · #4 04-16-2006, 09:19 PM

As it posts a code, it would have to be a wiring problem back to the C solenoid, the Solenoid itself, or the TCU.

If it was just the clutch plates binding it would not post the code.

Can't think of any thing else Tom.

Harvey.

Tim · #5 04-17-2006, 04:19 AM

Yea in my car once I put the FWD fuse in all the problems cease. This is the list of problems I had on my old tranny before my awd gave up completely:

1.Binding
2.A thunk/clunk when I came to a complete stop for like 10 seconds. It felt like I shifted into park when cold and shifted into drive.
3.a light thunk when gassing it, that's how I knew the rear engaged.

Manarius · #6 04-17-2006, 06:14 AM

Tom, are you binding on sharp/slow corners? This would make me lean much more towards the center diff. Over time, the 4EAT's will start to torquebind, and the source of this binding is the center diff (hence why when you put in the AWD fuse, nothing changes because the center diff is still powering the front wheels).

If you let this go, eventually you'll shear all the teeth from your center diff and you'll have a car that won't move.

TomsSVX · #7 04-29-2006, 01:59 PM

Took some more measurements today. At pin #3 I have the following voltages

Key on engine off
Closed throttle- 11.25v
WOT- .15 volts

Engine on
Closed throttle- 13.3 volts
Quick run to WOT in park- .35 volts(at least i think thats what I saw)

I double checked the TPS and it is showing .5v at idle and it does increase along with throttle movement. I have a feeling more and more that it is the actualy solenoid itself. Later I may have time to get under it and measure voltage off of the sol. C wire entering the transmission to see if I am losing it in the harness somewhere. If not I will split the ass end of the case open and check volatge at the solenoid itself. I may just have to buy a new solenoid but I want to be sure first.

Tom

nipper · #8 04-29-2006, 04:11 PM

I'm sort of an expert on torque bind on the other soobie board. i just posted this to another thread i hope this help. The autos dont have a center differnetial, the manuals have one, in conjunction with a viscous coupling.

http://www.subaru-svx.net/forum/showthread.php?t=32960

i have a beutiful description from subaru on how the 4eat transmission works if anyone wants it.

nipper

oab_au · #9 04-30-2006, 01:30 AM

Tom I think it there is confusion on the C solenoid. The one on the US model is different to the VTD model. I have written about it before some where. The one in yours, turns FWD, when on full signal. With no signal, the transfer clutch is full on.

The VTD is the opposite, no pressure with no signal, full pressure with full signal. The difference is in the C solenoid, the US one is normally closed. The one in the VTD is normally open. I guess that this was to allow the units to "fail safe" differently.

Yours defaults to 50/50, ours to no Limited Slip Clutch.

This the VTD unit, but your hydraulics are the same.

You can see that the C solenoid bleeds off The yellow pilot pressure, to reduce the pressure on the transfer spool valve so that the spring can move it across to turn the RED line pressure off the transfer clutch.

For it to bind, either the transfer valve has to stick in the on position, or the C solenoid is not fully bleeding off the pilot pressure, to hold the transfer valve on.

It your case I think it is the C solenoid that is not opening fully. Maybe it has a mechanical problem to prevent full armature travel, or there is some foreign body stuck in it preventing full travel. There is also a chance that the duty cycle signal is reduced by a resistance somewhere, though I don't know if the TCU could detect that, to post a code.

Harvey.

TomsSVX · #10 04-30-2006, 09:47 AM

Ok so this confirms my suspicion that when the solenoid does not have an ~12v signal the transfer clutces are fully engaged. In this case I know what I am looking for. Thank you guys and I will keep you updated as I have time to work on it

Tom

TomsSVX · #11 05-08-2006, 07:51 PM

Ok, finally got it up in the air tonight and did aquickl test. Turns out that my sol. C is working and it is working properly. With the ignition on/engine off, when I hit the throttle, I can hear the sol. cycling. As I open the throttle, the solenoid cycles less and less until it doesn't cycle anymore at/close to WOT. So, Why the hell am I having a binding issue and why is the Sol C code comming up?

Tom

Trevor · #12 05-08-2006, 09:08 PM

Quote:

Originally Posted by TomsSVX

Ok, finally got it up in the air tonight and did aquickl test. Turns out that my sol. C is working and it is working properly. With the ignition on/engine off, when I hit the throttle, I can hear the sol. cycling. As I open the throttle, the solenoid cycles less and less until it doesn't cycle anymore at/close to WOT. So, Why the hell am I having a binding issue and why is the Sol C code comming up?

Tom

Reference your message in another thread. I do not hide behind an alias and am pleased to provide my phone number and address. Trevor R. Sheffield, 16A Seaside Avenue, Waterview, Auckland, 1007, New Zealand. (nz) 09-8208553

However please hold off phoning until I have had time to mull over your dilemma and I will come back here, or by PM. Meantime my thought is that the valve could have something preventing full travel, e.g. on the seat, but could still be moving enough to be audible. What do you think ?

TomsSVX · #13 05-08-2006, 10:15 PM

its a good possibility that is the case but it still boggles my mind. The battery in the car is dead right now because I don't have the time or spare cash to throw at this car right now. I will get a jump pack tomorrow and jump it again and see if it is possibly fixed. I was fiddling around with the harness before I did the test so maybe I cleared up a bad connection i don't know

Tom

Edit: Damn, you are in New Zealand, sorry man but those charges would kill my phone bill, thanks though

TomsSVX · #14 05-13-2006, 12:19 PM

Well, thanks to SVXfiles, I have installed a whole new tailshaft. The FWD lights comes on now. I have yet to take it down off the jackstands but it is family time now. I will take it for a spin tomorrow or later on tonight when I take it down

Tom

TomsSVX · #15 05-15-2006, 11:30 AM

It's ALIVE!!!! The new tailshaft has fixed all ailments. My guess is that there was an abstruction of the transfer valve in the old housing which would not allow it to actually cut the line pressure. I know the Sol. C was working but the transfer valve was not. So all in all it was a good day

Now I need to go get it registered and try to get it passed by the inspection o Joisey. Anyway, thank you all who helped, this car is now running well and I am very grateful since I amy decide to blow up my silver one soon

Tom