Just got onto this site yesterday- Brilliant!
I've got a 92 GT legacy wagon which has slowly been losing and has now completely lost drive to the rears. I pulled the codes from the TCU and it checks out fine. TX was rebuilt at 74,000 and is now on 146,000.
Front end is always lighting up on heavy starts (Looks cool).
I've got a lot of good info of this site and have come to the conclusion that duty solenoid C is'nt playing the game. Had a nose underneath while it was on the hoist and everything is intact. The back wheels coast around in Drive when shes up there and I can stall them by holding the prop shaft so I'm guessing the AWD clutch is fine but that solenoid isnt.
Long winded history huh.
Can anyone send a scan that covers the centre clutch unit and the location of the duty solenoid with info or a solution to my prob?
Anything would be awesome!
Update:
Changed the tranny fluid and it was a bit brown after 80,000kms.
has made some difference to the AWD but i can still stall the back wheels by hand and the 4wd clutch pack still isn't engageing. I checked the filter and it was fine. The sump magnet had the usual grey metal paste stuck to it but nothing out of the ordinary. Is there a way of checking the function of the duty solenoid C and the two shaft speed sensors to make sure they are O.K.? There are no fault codes in the TCU.
Problem sorted at last.
I pulled the transfer case off the back of the tranny and it turns out the friction plates in the AWD clutch are worn down to the point that the piston that pushes on them has reached it's max travel hence no 4wd. everything else works fine. NZ$60 for a new set. I'm a bit that they flogged out after only 80,000kms but an easy fix none the less.
Ripper!!
Bah! back to square one. All back together and no change, still no AWD.
Duty solenoid is OK so now I will check harness and then voltage output from tcu. I just have to identify which pin on the tcu to check. Also the speedo isn't working and i'm sure i plugged in the speed sensor. I will check it tomorrow. Took it 4 a drive and after about 5 km the engine stopped and check engine light came on. It would start then stop. Turned of completely and restarted fine just the check light was on. Drove home and the radiator fans were running nonstop. Pulled a code from the ecu - 33 which is the veh speed sensor.
92 GT Legacy wagon for australasian market.
Oh god I'm going out of my mind now. Fixed the speedo, just the cable had popped out the back of the gauge.
All back together, no change. Went to the local subby specialist and they plugged their diag tool in-no problems at all. Everything works just no awd.
AARRRRRGGGGHHHH!!!!!
Next step-check trans line pressure thru test port.
Where is it and how do I test or is it better left to the experts- As always cash is short and I just got hitched so now I'm really flat broke!
Id say check the signal going to the duty c solenoid.
I cant ever remember, but 0% duty cycle is fully locked and 100% is fully open right? If so couldnt you just disconnect the electrical portion and get full lockup? Put the car on jack stands and have it running but in neutral. The center diff should be locked in this state.
Damn, that was quick! Do you guys sleep?
To test I've had it on axle stands all round and in drive the fronts tick round as do the rears but I can stall the rears by hand. Also had it on the grass and the front spins up but nothing to the rear e.g. I can have the hand brake on and the fronts spin but the rears are stopped. The connection for the duty c is inside the trans. The only way to disconnect that I can see is to identify the wire on the the connector block that joins to the harness and remove it from the block, but which wire? Means lifting the intercooler off. Need a 92 gt legacy wagon schematic I s'pose. duty c has a resistance of 13 ohm's and it's supposed to be between 10-15 ohm's so all good there. BTW with the speedo unplugged she fairly flies i.e. no cutoff at 185kph. Dunno what kph this model is good for but hell!
There is no centre diff in this as it is an auto, just a clutch pack. With no voltage from the TCU the awd is 50/50 by default, but with voltage it is 90/10 to the front. Pulses from the tcu regulate the %duty of the solenoid.
I.E. if the solenoid fails the drive becomes 50/50 until fixed.
Once again thanks all for you valued input. I would be lost without this forum
Back with a new
Talked to a guy on another forum and he had the same prob. He said he found the wire in the tx harness that goes to the duty solenoid c and placed a switch on it which he can control from the drivers seat, sort of like awd on command. Works well he reckons.
My question is would you have to place resistor on the end of the original circuit to fool the tcu or just not worry about it, 13 ohms would do nicely I think. Said he did 10,000 miles no worries and then sold it still working fine. I would have to rig up an led or something to illuminate when it's 4wd is on.
Snow starts here soon
Thoughts anyone
The TCU might be unhappy without a load on that circuit, but even if it were, it's unlikely that it would affect how the transmission operates.
One note -- if you do decide to put 13 ohms of resistance in, be sure you use resistors capable of handling that much power; a 20-watt resistor would be pretty safe.
It's been done, however what others have done is just put a switch inline.
When the signal is disconnected from the Duty C solenoid, it defaults to 50/50 torque split.
The signal going to the duty C solenoid is a PWM signal, so I think an adjustable POT might work. I'm not sure that's really needed though, since the computer sort of controls the adjustability of the AWD.
You really shouldn't put a potentiometer in line there; solenoid valves don't really work that way. PWM with them actually cycles them open and closed, as opposed to with light bulbs and motors where it gets integrated internally.
If you need an adjustable PWM signal, you can build a circuit to generate it. It wouldn't be that hard, but you'd want it to be as similar as possible to the TCU's signal, so you'd need to know what frequency it uses, how quickly it changes, etc. But I'm sure you could do it pretty simply -- generate a triangle wave of the correct frequency, and run it through a comparator with a threshold based on a potentiometer. The output of the comparator can drive a transistor to control to solenoid.
Heh... Then you'd mount that potentiometer as a thumbwheel on your center console near the handbrake, just like an STi. :)
Gt Tankie said "There is no centre diff in this as it is an auto, just a clutch pack"
So what would you call it, an infinitly variable transfer case? By the simplest definition of the term it is a differential, allowing the output to the rear wheels to get equal torque most of the time until the speed difference occurs, or in other words moving at different speeds. Sounds like a differential to me. So what if it doesnt have spider gears. The new subaru STI mechanical differentials dont have them either, yet they are still called differentials!
I know you all are going to think i am a total idiot but isnt it possible that when tranny was worked they installed the fuse that kills the awd?on auto they have to do this right?it seems a easy thing to over look.probably not but he has tried everything else it seems.
-Matt
'92 SS 5mt. All go and no show. Sold :(
'94 Audi UrS4 Modded (new project)
'96 Outback 5mt.
'07 Legacy 2.5i SE
[quote="Redlined"]
Oh... and I hope the fucker get bunked with Gunter, arrested for raping Gorillas.[/quote]
Legacy777 wrote:Well, probably the easiest thing to do is find the pin where it connects to the TCU and snip it back a little bit, and tie a switch inline with that.
Make sure you use a non-lighted switch.
Well in that case I'll just leave it alone, Thanks anyway...
98 Ford Contour V6 24V 5MT
98 Chevy Camaro Z28 LS1 6MT
91 Rio Red SS 5MT Sold
91 Flat Black Wagon L+ 4EAT RIP
91 Pearl White SS 4EAT RIP
that they flogged out after only 80,000kms but an easy fix none the less.
