Center Differential

[wirelessenabled]

Some background.  2000 OBW with 5sp manual 185K miles.

 

Driving down the freeway at 65mph.  I hear a barely noticed a squeal a couple of times.  30 miles later skidded to a stop with all four wheels locked up.  Got the car home and started looking in to it.

 

1. Car starts and runs fine. No physical damage anywhere.

2. Clutch engages and disengages although the TO bearing is now noisy.

3. Can shift through and engage all gears, but car stalls when I let out the clutch.

4. Put car up on jacks.  Spin a wheel and the other side of the axle spins the opposite way with no noticeable grinding or clunking.  Both front and rear differentials seem ok.

5. Took the rear driveline apart at the rear diff carrier.  Rear wheels act fine spinning the driveline if one is held etc.

6. Took out the transmission, time for a clutch anyway.

7. Still locked up from the input shaft to the output shaft.

8. Removed transfer case with center diff/viscous coupler and other gears.

9. If I put rods through the pin holes in the stub axles the transmission spins fine.  Can sort of shift through the gears.  No grinding or rough parts in the rotation.

10. Spiral retaining ring is still on the center differential. A little bluing at the small end and  near where the the holes to the spider gears are.  No noticeable damage.  Cannot get the center diff guts to rotate at all even using a screwdriver to pry at the small spider gears.

 

Where do I go from here?

 

Does this describe a failure mode for a center diff? Or something else?

 

Any ideas on how to decide if the center diff is bad? I do not have a spare serviceable center diff.

 

Ideas on how to check out the transmission?  I'd prefer to not split it just yet since there was no indication of any problem with the transmission before this incident.

 

Other ideas?

 

I have read most of the center diff topics on here and other forums but didn't find any ideas about how to test one.

 

Thanks!

 

 

[1 Lucky Texan]

wow

 

I have no useful input

[wirelessenabled]

Took an old center diff I had apart tonight.

 

The photos show all the parts inside the unit and a set of the plates of which there are maybe 20 sets inside.

 

There are 2 large orings, one on each end and a square cross-section type ring that seals the inner shaft.

 

The silicone oil is very thick, sticky and dark colored.  I made a huge mess!  The center diff seems very rebuildable.

 

Anybody ever tried to rebuild one of these Phase 2 ones?

 

The VW Vanagon guys seems to replace the orings and the silicone oil in theirs.

.

[1 Lucky Texan]

ivans imports has torn into them ;http://www.ultimatesubaru.org/forum/topic/134322-repaird-awd-center-diff/?hl=%2Bcenter+%2Bdiff

[86 Wonder Wedge]

The locking up almost seems like two different gears have engaged. With either a bad/broken hub or broken shift fork, when like 1st AND 3rd engage, the center shaft will lock up due to 2 different ratios being employed. I had a T5 do that at 70 mph, not fun mind you.

 

I don't see anything catastrophic going on in the center diff though... With the center removed, does the trans spin freely (via the input shaft) when in a gear or neutral?

Edited March 23, 2015 by 86 Wonder Wedge

[wirelessenabled]

The input shaft spins freely in neutral.  When I put it in a gear, first I think, it spins fairly easily for a turn or two and then still turns but is harder to turn.  Then after 1/2 revolution or so it spins more easily.  The output shaft is turning while this happens as well as the two stub axles.  I can only seem to find one gear, pushing the shifter shaft straight forward.

 

The transfer case/center diff is removed so should the axles be turning?

How much should I be able to rotate the shifter shaft?

 

I removed the oil drain plug to look inside and found a chunk of twisted up white nylon in the hole.  Maybe the remains of a nylon flat washer?  It is not the drain plug gasket which is metal and still on the drain plug.

 

When I first drained the oil I found one little piece of steel sheet that was twisted up.  Laid flat was about 1/4" square.  About 26 gauge or so.

 

Thanks for the help!

[Fairtax4me]

Can you move the input shaft forward/back?

 

For all 4 wheels to lock the problem is going to be in the trans itself if there is no physical damage to the center diff.

 

Split the case and you'll probably find something all fudged up in there.

[nipper]

I am going with your transmission ate something. When two gears are engaged at once your not going anywhere, all 4 wheels will lock up (or two if 2wd).

[wirelessenabled]

I'll try moving the input shaft.  Getting close to just splitting the case.

Thanks for the help!

[86 Wonder Wedge]

In neutral, you should be able to hold the output shaft (or stub shafts on the front diff) still while turning the input shaft. In gear, it should be smooth, but more resistance. Consistant, but more resistance. The presence of the nylon suggests a thrust washer was sacrificed and two parts are now bonding when you need to keep them separated (like the Offspring).

 

Rotating the shifter rod about 15-20 degrees off center should find you 2nd or Rev (pushing in on the shaft)

Edited March 24, 2015 by 86 Wonder Wedge

[WoodsWagon]

The light squeeling before it locked usually means a bearing seized. Nothing inside the center diff will lock up the transmission, but the bearings it rides on could possibly. I'd think they would spin in the case if they seized though, so I'd be looking at bearings on the input shaft or the front pinion bearings.

[wirelessenabled]

I cannot feel any forward or backward movement on the input shaft.  I need to wait to have help to carry out the other ideas.  Meanwhile I will study the transmission diagram to better understand it and to see where the nylon chunk may have come from.

[Gloyale]

Upper rear bearing toasted and seized. Nylon probably chunks of the oiling trays in the rear transfer. When the end of the shaft starts walkin backward, it chews a "ring" out of the middle of that oiling tray/block off

[wirelessenabled]

Thanks for the info. 

Is that scenario economically repairable? 

Or is a used donor transmission the better option?

[Gloyale]

Thanks for the info. 

Is that scenario economically repairable? 

Or is a used donor transmission the better option?

Depends on eh yet extent of the damage.

 

If the bearing has spun too badly in the case, the case is shot.....possibly you can "peen" the bearing landing and get it to clamp the bearing again, done that a few times. Sometimes need to replace the c-shaped spacer collar at the rear if it' ground up.

 

 

If any damage has occurred to the gearsset it's toast.

 

If the he damage is not too bad, repairing is a better option since then you know what's in there.

[1 Lucky Texan]

185K miles?

 

probably find a used trans from a wreck, even with a little warranty, with 1/3 those miles. maybe worth looking around car-part.com for prices to help decide which way to go.

Edited March 26, 2015 by 1 Lucky Texan

[Gloyale]

185K miles?probably find a used trans from a wreck, even with a little warranty, with 1/3 those miles. maybe worth looking around car-part.com for prices to help decide which way to go.

Very rare to find 15+ year old trans around WA that's got less than 100k

 

Most subies out here get the miles piled on. And folks buy up the good parts to keep them on the road for longer since the bodies don't rust out.

Edited March 26, 2015 by Gloyale

[1 Lucky Texan]

Very rare to find 15+ year old trans around WA that's got less than 100k

 

Most subies out here get the miles piled on. And folks buy up the good parts to keep them on the road for longer since the bodies don't rust out.

 

 

fair point but, won't some newer year trans also fit?

 

still, it's easily $1,000.

 

if he found someone parting a car out, might do a little better?

 

I suppose if it was only plastic that got ground-up and circulated, little actual wear took place.

Edited March 27, 2015 by 1 Lucky Texan

[Gloyale]

fair point but, won't some newer year trans also fit?

 

still, it's easily $1,000.

 

if he found someone parting a car out, might do a little better?

 

I suppose if it was only plastic that got ground-up and circulated, little actual wear took place.

Compatible up to about 2007 I think. So maybe newer one possible

 

If he can do the work himself the bearings and seal are only about 200~300 bucks.

[wirelessenabled]

Thanks for the info!  I have a friend who says he has a line on a used transmission with 120K miles on it for under $500.  I haven't opened up the transmission yet waiting to see if that pans out.  I have also been looking on car-parts.com.  Most of them anywhere near are in the 150K mile range and about $800.

 

Thanks for the info on a possible repair to this transmission. There are three of these Subies in the immediate family so at some point I will be opening up the case for a look.

[wirelessenabled]

The transmission I had hoped to get didn't work out.  Work has intervened so I sent the transmission off to a friend.  He will open it up and let me know.

[wirelessenabled]

Original transmission was bad.  I found a cheap JDM dual range to swap in to the car.  Planning to just lock the D/R lever in to high range. 

 

Anybody know which way to put that lever on the transmission? 

 

Towards the front/bell housing or towards the rear/output shaft?

[wirelessenabled]

To complete this topic, I installed the JDM dual range transmission today.  If fit in fine with no problems.  Car drives nice now!

 

To answer the dual range lever question above ... the lever on the transmission is put to the rear for high range.  I just zip tied it in that position.

 

Thanks for all the help getting this car back on the road.

[wirelessenabled]

Just a follow up on this job.

 

The car is doing great, now approaching 200K miles or about 15K miles on the dual range transmission.  Fuel mileage has stayed the same as with the old transmission.  Have not tried to put it in low range but I am getting the itch to do that.  Maybe this Summer.

 

Only weird thing is that the clutch pedal is very "light" as in takes little effort to push it in.  I have the same Exedy clutch in my other '00 Outback and that clutch is harder to push.  The clutch works fine with no slippage or anything.

[comatosellama]

Just a follow up on this job.

 

The car is doing great, now approaching 200K miles or about 15K miles on the dual range transmission.  Fuel mileage has stayed the same as with the old transmission.  Have not tried to put it in low range but I am getting the itch to do that.  Maybe this Summer.

 

Only weird thing is that the clutch pedal is very "light" as in takes little effort to push it in.  I have the same Exedy clutch in my other '00 Outback and that clutch is harder to push.  The clutch works fine with no slippage or anything.

The things I'd do for a dual range ej box