Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

'96 5 Speed Center Differential Problems


  • Please log in to reply
14 replies to this topic

#1 jhelm_waterw

jhelm_waterw

    New User

  • Members
  • PipPip
  • 14 posts
  • philadelphia

Posted 26 June 2004 - 10:30 PM

Hi all and thanks for reading.

I have a 96 2.2 AWD Legacy Wagon with a 5 speed which means it uses the viscous coupled center differential.

Only in the last few months, I have been experiencing the '4WD Scrub' which means it binds up and shudders when turning a corner (Like my old switch on the fly locking 4WD Loyale)

This does not happen when the car is cold, only when I have been driving it for a while (once it is warm/hot). So... the magic silicone fluid that fills the center diff is getting hot and binding even when it should not.

I have all new matched tires which means that is not the problem.

I'm pretty sure I have just burned off/overheated too much of that fluid or beaten up my center diff towing too many heavy toys.

I was told 'Yep, it is shot. You cannot fix it, just buy a new one ($450). You have to drop the tranny, pull it apart and replace the diff as a whole unit'

Is this true? Has anyone heard of this? I have SEARCHED the net and come up with very few answers. No one really talks about the viscous center diffs.

Can I replace/refill the silicon fluid?
Are these servicable ?
Can I buy a used one? Where?

Thanks a lot in advance,
Jeremy

#2 hawksoob

hawksoob

    USMB is life!

  • Members
  • 205 posts
  • Atlanta

Posted 27 June 2004 - 01:06 AM

I have gone over and over various possible solutions to that exact same problem and finally looking at posts here and elsewhere, and getting an assessment from my dealer AND and independent specialist in Asian autos, my viscous coupling unit needs to be replaced. It is going to cost roughly $1K to do the job. The part is $450 (I've seen it online for $401, but this is not a DIY job for me, so it's going to have to be a dealer ordered part). It is a sealed unit and the silicon fluid cannot be replaced or refilled. The unit cannot be serviced. I'd say, even if it could, the labor involved in pulling the heiney out of the tranny PLUS rebuilding the unit would be close to the cost of replacing the unit.

My thoughts are this: It took over 150K miles for this thing to wear out. If I can get another 150K out of it for a grand? Why not? Averaging 12,000 miles a year, that comes to less than a quarter a day to get my VC back. So, looks like my new goal is to make it to 300K! :banana:

#3 jhelm_waterw

jhelm_waterw

    New User

  • Members
  • PipPip
  • 14 posts
  • philadelphia

Posted 27 June 2004 - 03:46 PM

Hawksoob...
Where did you see it online for $401 ? I am planning on pulling my tranny anyway when I replace the clutch and I am more than willing to crack that walnut to drop in a new differential. I dunno... I was even thinking of just drilling a FREAKIN hole in the side of the differential, adding some hydraulic fluid and mig welding the hole closed. Then maybe bench test it on a metal lathe as they discuss in an article I found online. Somebody out there has to have tried this. I can't be the only idiot on the planet who doesn't want to shell out $400+ for a new part.

I have gone over and over various possible solutions to that exact same problem and finally looking at posts here and elsewhere, and getting an assessment from my dealer AND and independent specialist in Asian autos, my viscous coupling unit needs to be replaced. It is going to cost roughly $1K to do the job. The part is $450 (I've seen it online for $401, but this is not a DIY job for me, so it's going to have to be a dealer ordered part). It is a sealed unit and the silicon fluid cannot be replaced or refilled. The unit cannot be serviced. I'd say, even if it could, the labor involved in pulling the heiney out of the tranny PLUS rebuilding the unit would be close to the cost of replacing the unit.

My thoughts are this: It took over 150K miles for this thing to wear out. If I can get another 150K out of it for a grand? Why not? Averaging 12,000 miles a year, that comes to less than a quarter a day to get my VC back. So, looks like my new goal is to make it to 300K! :banana:



#4 hawksoob

hawksoob

    USMB is life!

  • Members
  • 205 posts
  • Atlanta

Posted 27 June 2004 - 07:15 PM

subaruparts.com

Do a part number search on38434AA021

#5 georgeinmd

georgeinmd

    USMB Regular

  • Members
  • PipPipPip
  • 35 posts
  • MD

Posted 28 June 2004 - 01:08 PM

Jeremy,

Maybe you've read my thread Posted Image Viscous Coupling Unit? on this board. That's where things stand for me at this point. 1stsubaruparts.com quoted me a price of $360 for the unit (for a Forester). I think I will try replacing it myself when I just can't stand it anymore... -- George

#6 jhelm_waterw

jhelm_waterw

    New User

  • Members
  • PipPip
  • 14 posts
  • philadelphia

Posted 28 June 2004 - 01:39 PM

George,
Thanks for the reply. Your 99 Forester has the 'bolt on the rear' differential?
Yeah.. on my make/model the VC Center diff is buried inside my tranny housing and I have to take it down & apart to get to it. I read the entirety of your thread and found it informational but I disagree with a few people who posted there. This is my GUESS/OPINION ONLY. I definitely understand the proposed theory that if this unit was to fail it would fail OPEN. (much like a burnt out clutch) ie. no power being transfered to the rear wheels. However, I do not think this is quite as linear a failure. I think this is a two-step failure. I believe it starts by overheating the unit (like me pulling snowmobiles) and thus burning off or gumming up some of the precious silicone. This is only the start of the problem. Now, the viscosity has radically changed and the unit starts binding as soon as it gets slightly warm. This, in turn, causes way too much daily friction and, in turn, burns off even more fluid and, in time, ruins the disks. Then, one has an 'OPEN' failure. My little theory on 'why' they fail may be off-target, but everyone with whom I've conversed about this problem seems to recognize the first stages of the failure to be the dreaded '4WD scrubbing/binding' to be followed much later by complete failure.
BTW, did that other guy ever get back to you with where his mechanic found a Center diff for $250???
Thanks again.
jeremy

#7 georgeinmd

georgeinmd

    USMB Regular

  • Members
  • PipPipPip
  • 35 posts
  • MD

Posted 28 June 2004 - 02:23 PM

jeremy -- right, mine bolts on. (Subaru actually made something EASIER to fix?!). No, never got a reply on the source of the $250 unit.

I've pretty much decided there's nothing else it could be, and, as I said, a local mechanic agrees. I'll post my experiences if and when I tackle the bugger.-- George

#8 wrxsubaru

wrxsubaru

    1000+ Super USER!

  • Members
  • 1,294 posts
  • Seattle Washington US

Posted 28 June 2004 - 06:50 PM

I thought when vcenter diff goes out when its a viscus, it just acts like a open diff.

If your replacing your center diff you can upgrade to a STI one for not that much more if any at all. There stonger, and have a stroger limited slip affect.

#9 jhelm_waterw

jhelm_waterw

    New User

  • Members
  • PipPip
  • 14 posts
  • philadelphia

Posted 29 June 2004 - 08:58 AM

WRX,
you wrote:
'I thought when vcenter diff goes out when its a viscus, it just acts like a open diff'.
I know what you're thinking. I thought the same thing initially. That is what I would guess would be the case but it is, judging from all the posts, talking to mechanics and my current experience, not the way they fail. They all seem to definitely become very sticky first (possibly for a VERY long time) then they eventually fail completely and go 'Open'. I have conversed with MB users who talk about them going on like this for years before eventually failing. I could sort of deal with the nuisance of the scrubbing when parking the car but this has got to induce rediculous stress on all the remaining parts of the drive line. Could you imagine driving around, on dry pavement, with an old 'switch on the fly 4WD' turned on all the time???
That is what it feels like sometimes (when it's warm & I've driven it a while).

Also, I wish I could swap the part out with a WRX part. But you are lucky in that your center differential is the new kind that bolts onto the back of the tranny. You do not have to remove your entire tranny to fix it. Mine, unfortunately is buried inside the main tranny case so I have to remove & disassemble the whole unit.

Thinking back, I probably know exactly when I damaged this unit. I was in Killington leaving a bar (sober!) at 2 in the morning when it was -20F out. I was trying to leave up a hill and had my jacket over the emer brake and did not realize it was fully on. I just gunned the mutha thinking I was having a hard time on the hill. It also turns out I was in 3rd gear at the time (from a stand still on a hill), but the tranny was so frozen and hard to shift I really thought I had it in first. My clutch almost burnt up entirely and stank up the car. There was also another stank I did not recognize. It had to be the gearbox. Really, my car smelled like a fire for 2 weeks.
One moment of stupidity... $$$ worth of repair.

#10 subeman90

subeman90

    Soobologist

  • Moderator
  • 2,779 posts
  • Akron PA

Posted 29 June 2004 - 09:35 AM

Not trying to scare anyone but one time in my (long since gone) 90 legacy 5 speed AWD my center diff was acting like you mentioned and not too much later it went bang and stopped dead right then and there. I think the internals comited suicide on the spot. Car had to be dragged from a parking lot etc.

Be careful.......
Matt

#11 georgeinmd

georgeinmd

    USMB Regular

  • Members
  • PipPipPip
  • 35 posts
  • MD

Posted 29 June 2004 - 09:42 AM

I'm also noticing a loss of lateral traction, especially on wet roads, as it becomes tighter. Hmm, maybe sooner is better than later. Thanks for the insight, Matt. -- George

#12 hawksoob

hawksoob

    USMB is life!

  • Members
  • 205 posts
  • Atlanta

Posted 01 July 2004 - 05:25 PM

Well, a new VCU and $921 later (as of about 20 minutes ago) no more binding/grumbling on sharp turns after a long drive.

Hope this one lasts 150K!

#13 jhelm_waterw

jhelm_waterw

    New User

  • Members
  • PipPip
  • 14 posts
  • philadelphia

Posted 02 July 2004 - 07:29 AM

Hawksoob,
$921 ? Yowee.....
Ok, if that is how much it costs, that is how much it costs.
Yeah... your tranny should be good for at least another 150K.
Did they give you the old VCU?
Can you get it? I can give you a few bucks for it (like $50 plus shipping?)
I am on a mission. I want to get a 'bad' one and crack it open.
I am willing to blow $50 just to see how these things tick.
Whadya think? Can you ask the mechanic for the spent unit?
I have some theories about these things that I need to test.
Thanks
Jeremy
p.s. email me !

#14 georgeinmd

georgeinmd

    USMB Regular

  • Members
  • PipPipPip
  • 35 posts
  • MD

Posted 02 July 2004 - 07:47 AM

Jeremy -- please let me know if you figure anything out. Thanx! Incidently, around $1,000 is what my mechanic estimated for the same job. -- George

#15 hawksoob

hawksoob

    USMB is life!

  • Members
  • 205 posts
  • Atlanta

Posted 02 July 2004 - 08:59 AM

Hawksoob,
$921 ? Yowee.....
Ok, if that is how much it costs, that is how much it costs.
Yeah... your tranny should be good for at least another 150K.
Did they give you the old VCU?
Can you get it? I can give you a few bucks for it (like $50 plus shipping?)


I asked about the old one. He told me that there's really no way to tell if it's bad or not by just looking at it. It either works or it doesn't. I almost insisted I have it just as a keepsake, but I was just glad to get it fixed.

My original estimate was $1100. When I first took it in to be checked over (couple of months ago) The attending mechanic said he couldn't find anything wrong other than my tire pressures were all over the place: "One's 27, one's 19, one's 32, one's 22" Uh...dude....I check them almost daily in an almost unhealthy compulsive way. They are 34 in the front and 33 in the back. So, basically, for the check up I was charged $90 to be told I may need new brakes soon and to have my tires pumped up to the "proper" pressure of 38/36. Oh, I also wanted them to check a steering bushing that had apparently rotted away from previously leaking oil dripping on it and was hanging out of its perch. I was told, "He just pushed it back in." Riiiiiight..... I later found while underneath changing the oil that the rubber that was hanging down had been simply cut off. Needless to say, my first experience with this dealer was not the best.

I took it back a month or so later and talked to the big cheese service manager. Told him what was happening and then let him drive my car while I knew the problem was occurring. He immediately said, "That's your center differential/viscous unit. Seen 3 or 4 of them in the last year or so." He had an estimate for me in 10 minutes or so. (Although I was a bit concerned when he said, "Now, this MAY be the fix, but there also MAY be more to it. We won't know until we get in there." :banghead: Then, he offered me a dicsount considering the story I told of my displeasure on my previous visit.

After that, I took it to a nearby independent that specializes in Eurpoean and Asian motors to see about a second opinion. Big Subaru banner right there amongst those for Mercedes, Saab, and Toyota. They were A. somewhat familiar with what might possibly be the problem but B. unsure as to the actual procedure and part needed to fix it and C. unable to come anywhere near what the dealer had quoted me. They were very skeptical that I could get done what they perceived needed to be done for under $2k. I called a few other independents and none of them had a clue what was going on. Given this, I decided to just take it to the dealer and be done with it.

The service manager told me that half of the owners with this problem decided to just sell their vehicle and buy a new one because of the expense of the repair. I wouldn't have considered that. It drove beautifully before and it drives even better now. (I wasn't sure that straightaway driving would be affected by this problem since the differential only comes into play with different wheel speeds, but it seems like the AWD is there more than it was before. I does drive better in all ways). Driving the 2004 Forrester loaner they gave me made no impression on me whatsoever in terms of, "You know, a new car would probably suit me better." (Perhaps if they had lent me a WRX, the story would have been different. But, since I can't afford that, anyway, it would be a moot point.") I'm happy with my 9 year old OBW. :banana:




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users