Remove driveshaft to solve torque bind? 02 Legacy 4eat

[hankosolder2]

I have a family member with an '02 Legacy GT (4EAT). It has violent torque bind under certain circumstances...tires are matched, and evenly worn, no obvious issues, no trans warning lights. The torque bind is in the form of one or two really sharp jerking/ snapping sensations in low speed corners or backing up. It's not the more mild "shuddering" sensation I have experienced with other subies.

Dealership wants $1500 to (I think) rebuild the transfer clutches.  (I will get the exact details of their estimate later.)  Funds are very tight for the owner, I don't want to undertake repairing the clutches myself. Based on how violent the sensation is, I'm doubting that fluid flush and fills will solve the issue. (Perhaps I'm wrong?)

 

Would it be possible to pull the rear section of the driveshaft to make this car front wheel drive? Do the 3rd gen cars have a FWD fuse?

 

Failing that, are there any good indie Subaru shops near Grand Rapids, MI who might be able to beat the dealer's price?

 

Nathan

 

 

 

 

 

[chaz345]

I don't know about the newer generation having an FWD fuse, but I'm currently running my 93 Legacy without the rear section of the driveshaft because of intermittant torque bind and because one of the u-joints is failing and I don't want to have it break on the road. Had that experience once, not fun.  You should be able to have the transfer clutches done for a LOT less than that. Heck, you can have a whole used transmission put in for less than that. I've not done it myself but replacing the transfer clutches on a 4EAT isn't all that hard, you only need to remove the driveshaft and the tail section of the transmission. While you are there, check the Duty C solenoid too. Even if it's not bad to the point of throwing a code, it still might be sticking and contributing to the binding.

[hankosolder2]

OK, I got a copy of the dealership's estimate- they want to replace the prop/ driveshaft and the transfer clutch valve assembly (is this the Duty C solenoid assy with the valve body?)

 

I'm a bit puzzled why they want to replace the driveshaft. Presumably the U-joints are bad, but it seems odd that this would fail at the same time as the duty C....

[idosubaru]

1.  has this car ever "not" had torque bind?   meaning, was it bought this way or was major transmission/rear differential work done on it and maybe the final drive ratios are mismatched?

 

2.  need a proper diagnosis on the rear driveshaft - it works perfectly fine driving straight - no vibrations or noises?  a failing driveshaft ujoint will not only show symptoms while turning. 

 

rule out #1 first before doing anything else and answer #2 for us.

 

otherwise - YES, you can easily remove the rear half of the driveshaft and install the FWD fuse by the passengers side strut tower. can drive the car indefintely like this, as long as they want to with no damage.  might be a simple cover plate over the front of the diff, otherwise it's simply 4 12mm bolts on each end of the shaft that need removed.  can be off in a matter of minutes.

 

sounds like the dealer is throwing parts at it, $1,500 sounds unreasonable with what we've been told so far.  my friend had a dealership in atlanta replace his Duty C solenoid for him - it was $250 labor (he had already bought the car).  clutches are only a few more dollars.   it's not that hard of a job, i wouldn't let that dealer touch it - they are VERY familiar with this job and shouldn't be quoting high prices for how routine it is for Subarus.

 

yes - it is highly unlikely both are bad....so a proper diagnosis needs to be done.

[hankosolder2]

This car has been in the family since new, has never had any major repairs aside from HG. (i.e. the rear diff and trans are the orginals.) It never used to have torque bind.

 

Unfortunately, I'm 200 miles away from the car now, so I have to rely on my memory of driving the car some time ago when the problem was just starting out. My observations _at the time_ were that the car was fine 99% of the time, no noise or vibration- but once or twice it bound so sharply when I pulled into a parking space that it felt like something was going to fail catastrophically in the drive train.

 

I'm going to advise her to get a second opinion and see what they say. If it's not more reasonable, then I will drive on up, pull the rear section of the driveshaft and be done with it.

 

Thanks for your thoughts, GG.

[idosubaru]

oh good, good to know the ratios are all the same.

 

part of me wonders if it's even torque bind and not something else, but you seem to have spent some time with it and probably know.  fine 99% of the time...then once or twice...that sounds odd, unless by 99% meant usually driving straight, mostly thru roads and the once or twice were the only times it was turned at a sharp angle.

[johnceggleston]

there is, should be, a fuse for thew FWD.

it is located in the fuse box under the hood in the corner closest to the transmission.

it should be marked FWD.

(the H6 VDC does not have one. not sure about the llbean.)

 

have her try that, ANY fuse will do.

there should be a spare in the fuse box.

the inside of the lid has the labels.

 

try it.

 

if that fixes it, i would try new fluid.

 

how old is the fluid in the trans?

how many miles on the trans?

if these numbers are the same it is time for new fluid.

Edited July 31, 2013 by johnceggleston

[chaz345]

OK, I got a copy of the dealership's estimate- they want to replace the prop/ driveshaft and the transfer clutch valve assembly (is this the Duty C solenoid assy with the valve body?)

 

I'm a bit puzzled why they want to replace the driveshaft. Presumably the U-joints are bad, but it seems odd that this would fail at the same time as the duty C....

If the torque bind has been going on for very long, it can put a lot of extra stress on the driveshaft u-joints so it's not really all that strange that they think it needs a driveshaft. The combination of torque bind and failing u-joints can create some very violent "juddering" and clanging and other mayhem. But like someone said, failing u-joits will manifest when driving straight too. But it can definitely come and go.

 

The thing is, the dealer price on the driveshaft is stupidly high when one can be pulled from a junkyard for like $40 at most.  The transfer clutch valve assembly is the Duty C.

 

At this point though, I'd definitely suggest finding an independent, subaru specialist to do the work since $1500 is WAY too high foe what we're talking about. Even "shotgunning" the problem and replacing the Duty C, the clutch pack and the driveshaft, should only be about half what they are being quoted. Duty C and valve assembly should be bought new and they run around $160. Clutch pack also new is like $200. Junkyard pull driveshaft, both pieces, $100 at most. So, rounding up it's $500 in parts and it's only a 2 to 3 hour(at most) job so even at $100 per hour labor $800 total is at the high end.

Edited July 31, 2013 by chaz345

[hankosolder2]

Well, this gets interesting. She took it to a local trans shop for a second opinion, and they claim it's the rear diff. Evidently, there are tons of metal filings and supposedly chunks in the fluid.

 

It's obvious that either the dealer misdiagnosed or the trans shop misdiagnosed. I sort of think that a tech who is unfamiliar with Subaru AWD might tend to falsely suspect the rear diff...so it's a bit of a mystery. 

[johnceggleston]

rear diffs are often blamed for torque bond  by rookies.

 

but it is hard to argue with metal parts in the rear diff fluid.

if that is true.

 

install the fuse.

[idosubaru]

****** Was diff low on oil?

****** Has the diff fluid ever been changed?
*** How many miles?

 

what he said - "rear diff failure" 99% of the time means misdiagnosis, so be careful. but no fault of someone being wrong, folks used to trucks or RWD or american stuff that fails more often wouldn't know how robust subaru rear diffs are.

 

two scenarios:

 

1. "suspicion often creates what it suspects" (c.s. lewis) they assumed rear diff and the otherwise normal material on the diff drain plug made them think they were right.

 

2.  they really saw huge chunks and it's bad.

 

i favor them being right based on your description of it being violent and the word "chunks" - that is never a good word. 

 

I'm hesitant though because...besides rear diffs never failing...diff gears usually make a noise and don't "come and go", they typically get worse quickly.  but this is a rear diff, not a front so the stresses may be a bit lower than the front and that's cushioning that some.

 

the good news is that since these rear diffs never fail there is no demand and prices are, or should be, miniscule to replace with a used one.  when parting out cars they're not even worth keeping, there's simply no demand.  and they're relatively easy to replace.  4 12mm driveshaft bolts and like 3 bolts hold it in place, drop, disconnect axles and done.

 

www.car-parts.com

 

make sure you match the final drive ratio of the transmission or you'll have serious issues.  normally yours has a 4.44 final drive (like all OBW automatics) but i do recall some weirdness around 2002 GT's...can't recall if it's with manuals or automatics but they changed final drive ratios at one point around that time.  if it is 4.44 i even have one of those lying around from when i converted mine to FWD.

[hankosolder2]

Turns out it is an '01. Still probably 4.44?  It's so irritating dealing with this long distance- totally conflicting diagnoses, ridiculous prices, etc. If the car was in town, I could do my own diagnosis, could pop a J/Y diff in there and or disconnect the drive shaft for pennies on the dollar. 

 

Gary, is it possible to non-destructively pull the rear half shaft axles out of the outer CV joints? I'm trying to figure out a way to fix this car for sure in a single trip if I drive up there to help her out. So, I'm thinking pull the rear half shafts (leaving the outer cup/splined shaft/axle nut ) and pull the rear driveshaft to the diff. But, it would be nice to have it be easily reversible so it can be fixed properly later. 

[hankosolder2]

I forgot about the questions! I do not know if the diff was low on oil. 160K miles on the car. I do believe the diff had a fluid change in the past at the dealer. 

[nipper]

160K it may also be a driveshaft, but 600 bucks of that repair is a new driveshaft, where you can use a good used one or a rebuilt shft for much less, I would go used. The clutch pacK is usually around 900 bucks. 

[idosubaru]

the axles are difficult to disconnect from the outer joint, i had to work mine hard to get them to separate in order to convert mine from 4WD to 2WD and install those CV's back into the hub assembly.  it's been awhile since i did it but almost positive it wouldn't have bee reusable.  someone on here may know how to do that properly and easily, i do not.

 

maybe you could find a set of rear EJ axles and disassemble them for those parts you need.  someone on here may even have them, folks that have a parts car don't care about them, i always throw them away because there's no demand.

[lmdew]

Where is she located, may be there is a USMB member close by that could help. 

[johnceggleston]

suggestions:

 

usmb members close by, a good pair of eyes may help a lot.

parts yards close by, if the parts you MIGHT need are all easily available there is less need to carry parts up there.

 

put in the fuse and see if that helps.

if yes, then removing the drive shaft will ''fix'' it.

if no, then either swap the rear diff, or remove the rear axles and drive shaft as mentioned.

 

but chances are good all the parts you need are already up there, in one yard or another.

 

 

www.car-part.com

[hankosolder2]

Well, I'm not sure I want to burden any USMB folks with my family members! She's taking it to yet another shop on Monday, we'll see what they say and take it from there. Thanks to all for their suggestions so far.

[hankosolder2]

Independent shop #3 also says it's the rear diff. She's probably going to have them fix it there- at a price which will have USMB folks cringing.  I'll report back with the outcome in case anyone is curious.

[johnceggleston]

see if you can get the shop to agree to no charge if the problem is not fixed.

 

call the shop your self and act as her dad looking for re-assurance.

 

the worst case here is that they ''fix'' it for $600 but it is not fixed.

and then they want more.

 

just try to get them to commit, ''if this does not fix it , no charge''.

 

once you pay it is too late unless they are an above average shop.

 

god luck to you both.

[nipper]

Well, I'm not sure I want to burden any USMB folks with my family members! She's taking it to yet another shop on Monday, we'll see what they say and take it from there. Thanks to all for their suggestions so far.

But that is what we are here for.

[Fairtax4me]

Not hard to imagine that severe torque bind for such a prolonged period of time has caused the failure or excessive wear of the rear differential and ring and pinion gears. The ring and pinion gears have the job of transferring driving force from the driveshaft to the differential carrier, but those driving forces work both ways. If the drivetrain is binding the stresses on the ring and pinion gears increase exponentially. Really the part that is LEAST affected by torque bind is the transmission. The differentials, driveshaft, and half shafts bear almost all of the brunt from torque bind.

 

I would also have to question the condition of the front differential at this point, since torque bind will also cause accelerated wear of the front ring and pinion gears, and differential gears as well.

[nipper]

What he said. usually someone repairs the TB before it gets that bad but it can and does happen. 

[hankosolder2]

Well, the rear differerential was replaced by indie shop #3 and the car supposedly drives just fine now. So I think the rear diff failed due to something other than the strain caused by torque bind- or we'd be back to having torque bind symptoms. As I mentioned in my first post, the "binding" sensation I experienced when driving the car was different than anything I'd experienced in a Subaru suffering from torque bind- it was a sharp, snapping "WTF was that?!" type of sensation, not the shuddering/chattering sensation of normal torque bind.

[nipper]

Yup sharp snapping no more give left in the viscous coupling. It would be the same as an old 4wd in 4wd on dry pavement. Actually I am surprised the car is even controllable as sometimes at that point wet roads can make trees look too close for comfort. You are feeling the driveline build up torque then snap like a rubberband