No drive to the rear

gt tankie · Post by **gt tankie** » Tue May 20, 2003 8:22 am

oh dear. Seems the topic notification wasn't sending me messages about this thread.

So here is an update,
I'm at a loss, yes there is no fuse fitted. The only thing I can think of now is a fault in the wiring loom but the OBD tool said all checks out fine.
Next would be line pressure to the duty solenoid valvebody but how can I test this when it's all inside the tranny and the tranny must be running?
The car is running really well otherwise

Ciper those trouble shooting scans would be a tremendous help as I don't have a tech manual.

Stop the world I wanna get off

gt tankie · Post by **gt tankie** » Tue May 20, 2003 8:54 am

Just a further thought.
I've just delved into the logic bit in my brain and come up with this:
The duty solenoid is fine, the computer is fine and the loom is fine.
If it was'nt it would be 50/50 awd by default right? I.E. no signal to the solenoid. So to my mind that means I have a lack of or no oil pressure to the valve body and clutch piston. Would the lack of pressure also affect other components or are they on separate lines?
Does anyone have a logical step by step elimination process to identify the fault? The trans shops and scoob dealers want considerable sums of my hard earned cash to do this and I have no gaurantee that this will help.

Snow is here soon and no one likes to see a grown man

Post by **Legacy777** » Tue May 20, 2003 2:28 pm

I think you're probably onto the right track with line pressure.

There is a service port you can tap into to see line pressure. I'm not sure if it's just line pressure for the entire system or for the rear transfer clutches.

Also, another thought is there is a seal leaking somewhere. If this is the case under slip conditions the duty cylce of the duty c solenoid should decrease

If you have a scan tool, you may want to drive around with it and watch the duty % of the solenoid and see what type of behavior it exhibits.

Post by **Legacy777** » Tue May 20, 2003 2:32 pm

One thing I forgot to mention. Move the gear selector to the 2 position. Leave it there and read the duty c solenoid %. It should be decreased compared to when it's in D. The TCU is supposed to put the car in 50/50 mode when the gear selector is in 2.

gt tankie · Post by **gt tankie** » Sat May 31, 2003 12:54 pm

Got a Haynes manual today NZ$76 comprehensive but nothing on the 4EAT internals. The book had a plastic cover on it so I couldn't have a read before buying it. The PUNK at the counter assured me it was covered but as usual the guys selling don't know their product. It only covers the removal and external repairs/adjustments.
Still worth having for all the other stuff in it though.
So I'm asking a big favour scoob people, if anyone has access to legacy/liberty TECHNICAL workshop manual can you please scan by whatever means the chapter pertaining to the 4EAT internals and email to me off list. tankie@xtra.co.nz
Front wheel spin is embarrasing

gt tankie · Post by **gt tankie** » Sun Jun 01, 2003 6:41 am

Disemboweled the car today. Checked the voltage output from the tcu and it is within spec as is the trans wiring loom and solenoid.
When in drive with no accellerator the duty c is recieving around 9.5vdc i.e. low duty.
The further you press the accellerator the lower the voltage-full duty all th way to 0vdc.
So it is working as it should but still no AWD.
So whether the solenoid is open or closed, with no oil pressure the clutch won't actuate right?
Does anyone know where this pressure is developed and it's path to the duty c?
I fear a trans removal and tear down

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Post by **Legacy777** » Sun Jun 01, 2003 7:43 pm

Pressure is coming from the pump that feeds all the rest of the tranny.

Have you tried applying voltage to the solenoid while the car is off to see if it makes any clicking noise?

gt tankie · Post by **gt tankie** » Mon Jun 02, 2003 2:36 am

I tried that yesterday but can't hear thru all that metal. I can say however that when I had the solenoid in my hand I did apply 12vdc thru it and it was clicking open/shut. I blew air thru just to make sure it was working as well.
Today i will bolt the computers back up under the dash and test drive.
I have removed pin no 11 on the trans connector. This has disconnected the duty c so I should get awd 50/50 by default. If not then maybe the duty c valve body is sticking but it was fine when i had it out. we'll see.
You say that there is line pressure. I'm assuming this is correct otherwise the whole tranny would have died. If this is the case then the problem lies in the extension case because electrically everthing is fine.

gt tankie · Post by **gt tankie** » Mon Jun 02, 2003 4:46 am

Went for test drive on some grass and with the wire going to duty c disconnected it still only drives the front wheels

Cunning plan time!
A local garage has a tt legacy with a slush box that is an insurance write off sitting in the yard. I know the guy well and will see if i can pull the extension housing off and stick it on mine.
the confusing thing is if the solenoid has no current going to it it should be 50/50 drive by default right?
that leaves only the valve body at fault.

Thoughts anyone?

Post by **Legacy777** » Mon Jun 02, 2003 4:56 am

You're concentrating a lot on the duty c solenoid. I did say the rear is driven by line pressure, however it has to get back there some how, and if there is a leak in a seal or something blocking the passage way, you won't see much line pressure, or enough to make the rear wheels go.

That would be the next step IMO. See what sort of line pressure you are having to the rear extension housing. If pressure is good and solenoid is working, I would say the clutch packs are either not working, or there is a leak somewhere in the internals of the rear extension housing and not building pressure up.

gt tankie · Post by **gt tankie** » Mon Jun 02, 2003 5:37 am

You are right, I'm getting tunnel vision here.
Where do I tap to read pressure?
Thanks for your input guys (and girls if any)

91White-T · Post by **91White-T** » Mon Jun 02, 2003 6:37 pm

I also tried diconnecting the duty C wire, and still got nothing to the rears. After bringing it to te dealer, with the wire reconnected of course, they said there was a line pressure failure and would have to take the trans apart

gt tankie · Post by **gt tankie** » Thu Jun 05, 2003 6:18 am

This world is weird at times but MY AWD IS WORKING!!!
Went to the mechanic today and he is getting me the 4eat workshop/rebuilders manual on CD for NOTHING!
I towed a dead ford for him while i was there, heavy junk.
Then when I was leaving I did a full lock left turn on gravel and the rear axle started binding and a grin did spread across my dial as I realised that that godforsaken clutch had engaged. So after some quick launches from his yard on the metal whilst hanging out the door I confirmed that all 4 were spraying gravel like a mad womans piss.
And here is my little secret:
A few days ago I disconnected pin 11 on the trans harness connector in the hope that the awd would default 50/50 drive, but it didn't work sooo I left it off in the hopes that something magical would happen.
My theory is as follows: the valve body that is controled by the duty solenoid c was stuck and the constant line pressure over the last few days has popped it free. The towing of the heavy Ford rubbish must have placed extra line pressure on the valve body for the final push. Fords are good for something aye.
Make any sense?
My only problem now is I have to take off the intercooler to reattatch the no 11 pin for awd control. I suspect because the trans oil wasn't changed for 80k grit and grime fouled the valve enough to jamb it. The new fluid must have helped.

Anyway, thanks all for your valued advice this last few months. It's been a real learning curve, one i'm sure will continue.
Ilove these cars

gt tankie · Post by **gt tankie** » Fri Jun 06, 2003 10:05 am

BAH BAH BAH!!!

Hooked up that wire today and it's front wheel drive AGAIN!!
ARGGGHHH!
No more screwing around. I'm putting a switch on that wire so it will be awd on demand cos I cant leave it disconnected in 4wd. It's no good for the diffs cos I get torque bind on sharp turns.
Get it fixed when some cash comes my way.

herr_diesel · Post by **herr_diesel** » Tue Jun 24, 2003 8:01 pm

so what's the latest on your tranny? did you put a switch in? if so how did it work? this is exactly what i've been wanting to do in mine. give us the deets!

thanks gt tankie

gt tankie · Post by **gt tankie** » Wed Jun 25, 2003 1:41 am

Here's what I did:
I'm assuming you have an auto. First disconnect the battery!!!!! remove all the plastic junk around the gear shift until you have exposed the electric switches and wires.
On my model there are 2 buttons on the stick, 1 for the actual shifting(unlocking) and the other operates the manual mode i.e. when closed it wont use 1st or 4th( for snow or icy conditions). This function can be lived without so this is the switch I used to operate the awd. There are 2 wires running up the stick to this switch. Cut them both and tuck the wires away with some insulation tape on the ends so they wont earth out.
Now locate the TCU. On the jap model 92 gt legacy it is located on the drivers side under the dash(US model on the right) TCU location may vary dependant on model year market etc. On mine there is a panel above the foot well which must be removed. Behind glove box on US stuff I suppose. Remove the TCU and locate the no: 11 wire that goes to the B55/B68 connector, this is the duty c solenoid wire(AWD control). Snip it an inch or 2 away from the plug and bare both ends ready for soldering.
Get a length of wire the same gauge or bigger and solder it to one of the wires, which one is not important. Thread it along out of sight under the dash and along the top of the transmission tunnel( on top of the carpet as the fittings will cover it). Cut your great length of wire with enough to run up the stick to the 2 wires we cut first. Feed it thru the pivot point of the stick so it won't get stretched when shifting back to 1. Do the same with the remaining wire and attach it to the other wire at the TCU. We should now have a TCU with wire 11 on the B55/B68 connector cut and each soldered to the 2 lengths of wire routed thru to the shifter and up to the switch. Solder these 2 to the switch and wrap each joint with insulation tape. This is important as we dont want them to touch the metal shift column. Reconnect the TCU and then the battery. Start the car, with the switch out(open) you wil have 50/50 awd by default and torque bind in sharp turns, not good for diffs etc. Switch in(closed) the tcu will manage the awd for you. Be aware you will get a flashing green power light every time you start the car but will go away after a few secs. This suits me cos my duty c is sticking and wont give me AWD straight away but with this system it is freeing up with use.
This mod is of course totally reversable. If you want front wheel drive on demand(for smokin up or popping diffs) wire this circuit to the fwd fuse uder the hood instead of the tcu.

BTW no responsibility is taken for any damage incurred. Make sure you have an understanding of how this circuit works. It's just a means of opening or closing the circuit to the duty c solenoid-quite simple.
Have fun!

dashton · Post by **dashton** » Fri Jul 11, 2003 6:02 am

Thanks for all the great info you've posted here. Ironically, I have the identical problem with my '90 legacy LS. I've tried everything you have with no luck - so I'm really excited to try and cut the wire from the computer to the duty-C solenoid. My only question is: where is the computer in my car, and will it be the same wire as yours. Has anybody else out there tried this on a regular legacy and do they know where the computer and wire are? I'd appreciate all the help I can get.

One comment: You mentioned that your valve seems to be sticking and so you've wired the manual switch in to keep working it loose. Have you considered any products like AutoRX or Seafoam Trans-Tune? In preparation for cutting the wire I poured in a can of Seafoam this evening and then took it for a spin. I only went a couple of miles, and I can already feel the difference in the way the tranny is working. The shifts are better, it doesn't hunt as much - just seems to work better. I've heard a lot of good recommendations about this stuff and I hope it helps clean it all out. Once I get AWD working again (hopefully), I'll change out the fluid and I think I'll be in good shape. I'll also post some more info on how it works over time. Thanks. Dave.

gt tankie · Post by **gt tankie** » Fri Jul 11, 2003 11:20 am

No probs!
Mine is just a faulty duty c sol and will need replacing. Even tho the resistance checks out fine, The sol is knackered-not opening when the voltage drops. It will sting me NZ$168 for a new one if I put it in myself which is no prob as I've had it out b4. The tranny mongrels want the whole extension housing and 600 bucks. They say "oh we have to replace the clutch pack, piston seals, dilithium crystals, impulse drive and blah blah blah"
I'm taking a stand to these pricks.....

WHO WILL FIGHT WITH ME!!!!!!

gt tankie · Post by **gt tankie** » Thu Mar 04, 2004 5:13 am

Finally my prob is sorted and the cause is so incredibly simple.
Firstly I will clarify a little history.
Trans rebuilt at 76k
Fluid left to run UNCHANGED for 80k
In the trans sump pan there is a ring magnet to collect steel particulate.
Trannies make a LOT of metal after a rebuild.
After 80k the magnet had collected so much metallic crud it couldnt hold any more. This allowed the fine metal in the fluid to continue to circulate.
NOW THEN, in the 4EAT there are a number of magnets namely
DUTY SOLENOIDS!!!!

These collect the aforementioned metal from the fluid and they start sticking causing all manner of control issues.
My prob (DUTY SOLENOID C STICKING) and the resulting loss of AWD was simply metal sludge inside the solenoid.
To fix this I removed the solenoid and submerged it in CRC and using 12V dc I cycled the solenoid a few dozen times.
WELL the gey sludge did spew forth so i pumped CRC through it while cycling it. A LOT of muck came out.
I now have it actuating at 5 VDC and disengaging at 1VDC
Before it wouldnt work even at 12VDC!!
I left the power/manual switch linked into the duty c circuit so I have CONSTANT 4WD ON DEMAND AS WELL AS AWD AS NORMAL.
From this thread I can see this is a reasonably common problem.

It's the simple thimgs that often cause the biggest problems.

ciper · Post by **ciper** » Thu Mar 04, 2004 5:30 am

Awesome. I might try that myself!

"This function can be lived without so this is the switch"
I dont agree at all. http://bbs.legacycentral.org/viewtopic.php?t=1468

gt tankie · Post by **gt tankie** » Sun Jun 19, 2005 2:16 pm

It's been along time but I thought I had better follow this up for the benifit of others.

I ended up replacing the duty c solenoid and things worked like they should and there has been no problem since.
I left the manual switch wired into the duty c circuit so I had 50/50 4wd on demand. Just have to remember to push the button in for cruising otherwise torque bind results but awesome in mud,snow,ice etc.
Today I reversed this mod to factory set up as the tcu awd control is instantaneuos anyway (plus I needed to do diagnostics on another problem and this function is required)

So there it is for your info.

Best regards too all,

Gary.

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No drive to the rear

No drive to the rear