Why is my Legacy acting like a front wheel drive?

[Damz]

Hi Guys,

First post, just joined, but have been lurking in the shadows for aaaages!! Have gained lots of great info from the forum, stoked its Kiwi based too!

Anyway, Iv got a 2002 BH9 wagon, EJ25 auto, non turbo. Iv just replaced the gearbox and rear diff (did diff as the ratio's may be different, numbers didn't quite match on the new gearbox) and now my wagon is FWD?!

Iv read about a solenoid you can short/jump to make it FWD, but I havent done this...

From what I can find searching, either the center diff is gone in the new gbox, or something about a clutch drum somewhere?

Any help much appreciated, I still have the original gearbox if parts are needed - issue was a wierd clunking similar to CVs, possibly the front diff.

Cheers for any advice!

[Joker]

whoa whole bag or worms there

firstly welcome to the forums

where in the country/world are you & sounds like you might want to get someone to look at it rather than internet-fix it

[Joker]

also what was wrong in the first place / what required those repairs?

[Damz]

Im in the Naki, a Kiwi too!

That bad you reckon?!

I was thinking of getting the transfer case or center diff out of the old box, attaching it to the new one, and driving happily. Just need some advice on narrowing down the exact issue, or other possibilities I haven't read about yet.

Taking it to a workshop is cheating!?.

[Damz]

Ah I see, my first post is confusing sorry. The original issue was the second to last line. The current issue is only the FWD thing, ONLY. Lol

[Guest]

F ked centre diff can cause issues. I could jack the front up and put in gear with handbrake on...fronts turned with rears locked up.

[pedro]

Have you checked to see if the drive shaft is still there..

[lachlan]

oh come on guys ,youve all failed

this car is an auto

autos dont have a centre diff , they have direct drive to the front wheels . and clutch pack to drive the rears . like a backwards gtr .

its something electrical . maybe u didn't plug something it ? checked fuses ?

Edited June 11, 2015 by lachlan

[Damz]

 pedro said:

Have you checked to see if the drive shaft is still there..

LOL!

I appreciate you checking that, but I certainly put that back in during the transplant!

[Damz]

lachlan, Thats bloody interesting.

I would have definitely guessed mechanical.

Im sure all of the plugs went back where they came from, but I will double check tomorrow when it's light. I will check all fuses as well.

Will keep you posted!

Edited June 11, 2015 by Damz

[Damz]

Fuses are fine, and all wires are back where they belong damn it. Wish it were that simple! I double checked that no one had tampered with the FWD solenoid - all clear. And the FWD light on the dash is not lit up.

Any other thoughts??

[lachlan]

what is the box out of ? there may be wiring differences between them .

useless bit of info its solenoid c and full power to it is fwd and no power to it is 50 50 locked 4wd

[Damz]

 lachlan said:

what is the box out of ? there may be wiring differences between them .

useless bit of info its solenoid c and full power to it is fwd and no power to it is 50 50 locked 4wd

Good point, the box is from an outback. Visually they're identical as you probably know, and all of the plugs went in fine.

The outback is still at the wrecker down the road, if theres any info I can grab to help?

Just been searching, and found that perhaps the TCU (Traction control unit?) is not able to "compute" the different diff ratios (if they are actually different). Im thinking of grabbing the TCU from the outback tomorrow, just in case. I also read that if I unplug the TCU, this will put the trans into limp mode, with only 3rd gear & reverse, and cause the clutch disc thing to lock up. If i turn a tight radius on concrete, it should feel as though I have a rear lock diff (clunky). If I dont feel anything, there is a mechanical problem in the drive line somewhere. Sound logical?

[lachlan]

the tcu wouldnt give 2 fks if you changed the final drive ratio , it would just think you are doing a 50 when you are actually doing 55 .

i agree with the logic of your un plug the ecu tho . you will definatly notice . in third gear it prolly wont even have the power to skip a wheel . will get half way round a figure 8 and feel like it wants to stop . or yeah it will fee like locked rear diff but more severe

[Damz]

So first thing this morning, jacked the car up onto 4 axle stands, put it in 1, and one of the back wheels was turning!

I stopped it with my hand, and the other rear wheel remained still, as it was.

This leads me to believe the clutch pack is probably buggered, would you agree?

I can still do the TCU test later tonight, and probably will, but I feel it's unnecessary.

[lachlan]

no . that leads to the clutch pack being in 99 % front split and 1% to the rears through "drag"( internal clutch drag" only .

[Damz]

Is that adjustable? The split I mean? Had to work late tonight, couldnt test the tcu but will do in the morning.

Cheers again

[lachlan]

the tcu decides the tq split based on varying wheel speeds . apparently it reverts to 90 ft 10 rear unless the fronts are slipping then it feeds towards 50 50 . i believe it is usually more 60 40 tho as you can drift an auto legacy on grass pretty easy without having the fronts spin heaps first .

do you understand the difference between a clutch pack and a centre diff . not a clutch pack within a diff . ? the auto transmission is only driven by gears to the front wheels . by the tcu deciding to lock up a clutch can it transfer some power to the rear wheels .