Jump to content
LegacyGT.com

AWD Shudder Problems


Recommended Posts

I have a 1995 subaru legacy with AWD. When turning the car, there is a shudder that seems like it comes from a locked center differential. It happens when I turn either direction, and going forward and backward. I have put a fuse in the FWD fuse holder under the hood and the problem went away.

 

Has anyone experiance this? Any ideas as to what might be wrong? If I can't come up with a fix, I'm considering putting a switch in the car to turn the AWD on and off.

 

One more question. Can I hurt anything running it in FWD?

 

John

Link to comment
Share on other sites

Sounds like you've got torque bind. Your Duty C solenoid has possibly failed, or there is an electrical problem and your car is trying to go to more of a rear bias than 50/50. See a good mechanic.

 

 

you Should be able to run it in Tow mode without problem. Just don't floor it as much, you'll stress your front axles and such.

Link to comment
Share on other sites

Had torque bind on a '93, I drained and refilled the trans several times to get rid of old fluid in the torque converter, also installed new tires to ensure circumference matched on all 4. No more problem, since this was done 3 yrs / 15K miles ago.
Link to comment
Share on other sites

I just went through this in November. Going around a tight corner, I'd hear the inside rear tire skipping. Or when I'd try to back out of a parking space and cut the wheel, the car would stop idling itself out of the spot. The AT light would flash a bunch of times on startup. What was happening is that as soon as power was put to the car, the center diff (actually stuck on the end of the trans) would engage the rear wheels. I'd get a clunk sometimes when the car was shut off, and that was the diff disengaging.

The bottom line is that the I had the trans flushed with about 20qts of new fluid because I was hoping buildups had caused the problem, but it was ultimately that solenoid that needed to be replaced (it's located in the center diff). I think the whole thing ran me $550 at a reputable local trans shop. FWIW, there's VERY little information out there about this problem, but it seems to strike a lot of people between 80K and 100K. My car made it to 110K.

Link to comment
Share on other sites

Is your car an auto? It sounds like a bad MPT. If it goes away when you put the fuse. I have done several of these at work. It's not a cheap repair. The back of the trans has to come apart. In parts at my dealer it's $900.
Link to comment
Share on other sites

I think this is an automatic-specific problem. My understanding is that the manual cars have a permanent 50-50 split, made by mechanical connection. The Autos use an electronic impulse to get the solenoid to engage the rear diff.

 

In my case, putting in a fuse didn't seem to do anything. I'm not sure why; maybe it wasn't a big enough fuse. But yes, the center diff is located on the rearmost part of the transmission and will need to be opened up. The part itself was only about $180 and that's with the shop markup (probably of about 100%).

Link to comment
Share on other sites

yes, the manuals use a differential, the autos have no center diff, they have a clutch pack. DS C controls the pressure on the clutches. when it gets power, the clutches release, when it looses power, the clutches lock.

 

if your solenoid really is bad, than a switch will not help at all, switches only work for manually locking the clutches, they can not be unlocked if the solenoid is bad or receiving no power.

the most obvious was to tell if your clutches locked is if your car handles like a 4x4 truck with the transfer case engaged. i suppose it could also be trying to lock or temporarily locking, maybe because of a computer problem or the solenoid.

if there is some sort of problem with it, usually the power light will flash 16(i think) times upon start up. but i dont know if that is always the case

 

i have heard that the FWD fuse works separate from the solenoid, but im not sure on that.

Link to comment
Share on other sites

  • 3 weeks later...
  • 3 months later...

Hi Guys sorry to hijack the post, but my question is the reverse:eek:, i own a 95 auto legacy lsi and i plan to race it on ice, i want my diff's locked all the time , in 1,2, 3 &d Is it possible to have a permanent fix or switch to engage the clutches to lock?

 

Tks C

Link to comment
Share on other sites

Actually, there is. You can modulate (or in your case, fix) the voltage to Duty Solenoid C. By changing the voltage to the solenoid, it will vary the amount of power sent to the rear wheels. There's a post about it at SL-I.net Do a search there for "duty solenoid".
Link to comment
Share on other sites

From what Ive seen, usually its either the duty solenoid, or the clutch packs starting to go. The repair isnt that bad at all, drop the exhaust, take off the drive line, support the tranny and remove the x member, take out the bolts around the tailshaft housing (I think their is 8) seperate the housing and you will see the solenoid on the left and the clutch pack is the piece that fits in the end. When removing the solenoid make sure the wire that runs from inside the trans does not fall back in, if it does you gotta drop the pan. Make sure you drain the fluid before starting and make sure you replace the drain plug gasket. Put everything back together, dont worry about torque specs just make sure everthing is tight but dont snap anything. Fill up the trans with fresh ATF and you should be good. If you want to check the clutch pack, you can measure between each one and there is a spec out there, I just cant remember what it is.
Link to comment
Share on other sites

Well it's been a while since I started this post and I thought I should fill you in on what I found. Those of you who suggested changing the tranny fluid were dead on. I changed it 3 times (driving the car for a couple of weeks between changes), and the problem has gone away. My brother also has a subaru that was doing the same thing, he changed his fluid, and the problem was solved.

 

If you are having the problem, thats the route I would try first, it's cheap, and seems to make a big differnece.

 

Thanks for all the posts.

 

John

Link to comment
Share on other sites

  • 2 weeks later...
Can any of you tell me how dirty your fluid was? My 96 GT is doing it but only when turning and coming to a stop. It hasn't started to cause wheel hop yet and isn't that severe. My trans fluid looks fairly clean. The dealer told me to change the fluid first and see what happens. I said the fluid looks really good and clean. Then he suggested that it may need the clutches or even the solenoid itself replaced. Thanks.
Link to comment
Share on other sites

I followed the advice and changed the transmission fluid. I have changed it once and have noticed a huge improvement. 2 more times should take care of it. I was ready to go to the dealer and spend a $1000 to have it fixed. Thanks to the advice of the other members. I was surprised to find that when I drained the fluid it was dirty and the transmission had been over filled by about 2 quarts. I will update over the next few weeks as I drain the old fluid and new fluid. Thanks again.:)
Link to comment
Share on other sites

  • 4 months later...

I'm having the opposite problem. My 95 Legacy L AWD is forever stuck in FWD mode. The A/T fluid temp light would blink on startup, and I got the solenoid and clutch pack from a car that was having the binding issue, figuring I could fix it with those. When I installed it, the car now thinks it's all right, but it really isn't. When I put the FWD fuse in, it states "FWD" on the dash, when I pull the fuse, the light goes out. It all looks good from the outside, but it snowed yesterday and it definitely doesn't work. If anybody has any ideas, it would be greatly appreciated.

Thanks,

Kurt

Link to comment
Share on other sites

I'm having the opposite problem. My 95 Legacy L AWD is forever stuck in FWD mode. The A/T fluid temp light would blink on startup, and I got the solenoid and clutch pack from a car that was having the binding issue, figuring I could fix it with those. When I installed it, the car now thinks it's all right, but it really isn't. When I put the FWD fuse in, it states "FWD" on the dash, when I pull the fuse, the light goes out. It all looks good from the outside, but it snowed yesterday and it definitely doesn't work. If anybody has any ideas, it would be greatly appreciated.

Thanks,

Kurt

 

Rear diff is bad. In fact I just got the solenoid and rear diff replaced a week ago. I repaired it in the opposite order though. I knew the rear diff was bad but i didn't find out the solenoid was bad until I fixed the diff. The car is nice and happy now. With exception of the dreaded check engine light I received yesterday (probably the exhaust).

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use