Shudder at very low speed during sharp turning
Yousuf Khan
cornering at low speeds. I'm talking about parking maneuver type
situations. It seems to occur whether I'm turning left or right, just as
long as it's slow and sharp.
I've seen this type of shuddering before on this car, but those were
during cold winter days when there was a bit of ice that built up on the
joints, and they go away if you let the ice melt away. But it's nowhere
near winter yet, and there isn't a flake of snow on the ground right now.
What could this be? CV joints, or differentials (i.e. front to rear)?
Yousuf Khan
1 Lucky Texan
d@mn - most likely 'torque bind' . From mis-matched tires if you're
lucky, if not - center diff.
Some folks have found bad U joints on the drive shaft.
Carl
.._..
"1 Lucky Texan" <alck...@swbell.net> wrote in message
news:b12d960b-7316-4e61...@p36g2000vbn.googlegroups.com...
S
On Mon, 05 Oct 2009 21:36:50 -0400, Yousuf Khan <bbb...@yahoo.com>
wrote:
I'll assume you have done the obvious; check tires for wear/proper
inflation, check for visible damage (torn boots of whatever) on front
axles.
When was the last time you changed the fluid in the transmission? I
ask because we experienced a similar issue in my wife's '02 Forester.
After replacing both front axles without eliminating the torque bind,
I determined that it was being generated in the 5spd transmission,
specifically the "viscous coupling/center differential".
I was told various stories about repairing this, and finally ended up
replacing the transmission with a low miles junkyard box. At the time
this appeared to be the quickest and easiest approach, and did cure
the torque bind issue.
Subsequently, I disassembled the rear case of the original
transmission. It was kind of a b____ getting the cases to separate,
but otherwise fairly easy, and could undoubtedly have been
accomplished with the tranny in the car. Getting the center
differential assembly out was likewise easy (it sorta fell out into my
hands), and there didn't appear to be any special shimming or
alignment involved in putting it back together.
The "viscous coupling" part of the center differential was severely
gummed up, and couldn't be turned by hand. I tossed the entire thing
into my solvent tank for a couple days before taking it apart as far
as possible, cleaning, re-assembling, lubricating, and re-installing
it into the transmission.
Just out of curiosity, I swapped this transmission into my '99 Forry
(I needed to service the clutch anyway), where it appears to be
working just fine. Haven't put but about 1000 miles on it yet, tho, so
time will tell.
In any event, because of where the center diff lives (at the back of
the transmission in it's own chamber), it doesn't appear to get much
fluid circulation. This suggests to me that frequent fluid changes in
the transmission are probably indicated, and may well prevent the
viscous coupling from becoming gummed up.
If torque bind is starting to become evident, however, flushing the
tranny with light weight motor oil, or even Stoddard solvent
(kerosene) just might clean things up for you. Worth a try in any
event, as a new center differential assembly (you can't get just the
viscous coupling part) will set you back $550, while a new tranny is
$3500. I _only_ spent $500 on the junkyard transmission, but if I ever
have to do it again, I will try a flush as detailed below, followed by
replacing the center diff if the flush doesn't help. Live and learn.
My plan to flush the tranny would look like this:
Drain the existing fluid and re-fill with a light weight motor oil.
(10W30, or maybe some of the "Marvel Mystery Oil" stuff)(or Stoddard
solvent) Drive the car around a bit to circulate the oil. including
some tight "parking lot" maneuvers to work the viscous coupling. If
things appear to be improving, drain and repeat as desired. Finally
drain and refill with proper gear lube. If you use solvent, a final
flush with motor oil or gear lube is probably advisable to be sure you
get most of the solvent out of the transmission.
If you try this, do post a follow-up to let us know if it helped at
all.
ByeBye! S.
Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101
XR650L_Dave
I believe the center diff viscous coupling is sealed from the
transmission fluid, so changing the trans fluid will not have any
effect on manual-transmission torque bind.
Cleaning out the gummy silicone fluid will leave you with AWD as long
as no wheels slip, a wheel starts to slip and the center diff will
send all the power to the slipping wheel.
Still better than just front-wheel-drive, but not as good as a 50/50
front/rear torque split when a wheel slips.
Dave
YKhan
I did recently change the tires on this thing, about a month back, but
they are all brand new and exactly the same model. I'll see if there
is a tire pressure difference somewhere.
Yousuf Khan
OptoOne
Can you feel the shudder in the steering wheel? If so, then you may
be suffering from a problem that was inherent in Legacies and OBs of
that era. I had it in my 2000 Legacy Brighton wagon. The power
steering lines were too small in diameter, so at low speed there was
not enough pressure in the system and it shuddered. This was
especially true turning left.
For this problem Subaru sells an upgrade kit with larger diameter
lines, although they do not guarentee that it would fix the probelm
completely. I had the kit installed 5 or 6 years ago and the problem
pretty much went away. Only happens now in extreme cold when
pressure is low.
Gook luck.
YKhan
> Can you feel the shudder in the steering wheel? If so, then you may
> be suffering from a problem that was inherent in Legacies and OBs of
> that era. I had it in my 2000 Legacy Brighton wagon. The power
> steering lines were too small in diameter, so at low speed there was
> not enough pressure in the system and it shuddered. This was
> especially true turning left.
>
> For this problem Subaru sells an upgrade kit with larger diameter
> lines, although they do not guarentee that it would fix the probelm
> completely. I had the kit installed 5 or 6 years ago and the problem
> pretty much went away. Only happens now in extreme cold when
> pressure is low.
Yes, I can feel it in the steering wheel. It's very slight, it's not
like as if the wheel shakes visibly, just something I can feel through
the hands.
Interesting, I'll probably look into this if the tire pressures don't
fix it.
Yousuf Khan
YKhan
>
> On Mon, 05 Oct 2009 21:36:50 -0400, Yousuf Khan <bbb...@yahoo.com>
> wrote:
>
> >My 2000 OBW w/ 5MT has recently developed a slight shudder during sharp
> >cornering at low speeds. I'm talking about parking maneuver type
> >situations. It seems to occur whether I'm turning left or right, just as
> >long as it's slow and sharp.
>
> >I've seen this type of shuddering before on this car, but those were
> >during cold winter days when there was a bit of ice that built up on the
> >joints, and they go away if you let the ice melt away. But it's nowhere
> >near winter yet, and there isn't a flake of snow on the ground right now.
>
> >What could this be? CV joints, or differentials (i.e. front to rear)?
>
> I'll assume you have done the obvious; check tires for wear/proper
> inflation, check for visible damage (torn boots of whatever) on front
> axles.
I have checked the tire wear situation, but since these tires are so
brand new (a month or two), not a lot of wear patterns are visible
yet.
I haven't noticed anything wrong with the boots while the tires were
turned to one side or the other. But I haven't checked from under
since I don't have a car lift.
> When was the last time you changed the fluid in the transmission? I
> ask because we experienced a similar issue in my wife's '02 Forester.
That was done earlier this year. The front diff and transmission are
the same unit, so they both get changed at the same time. I think the
rear diff was also done at the same time.
> After replacing both front axles without eliminating the torque bind,
> I determined that it was being generated in the 5spd transmission,
> specifically the "viscous coupling/center differential".
That's a possibility, that's why I asked in here.
> The "viscous coupling" part of the center differential was severely
> gummed up, and couldn't be turned by hand. I tossed the entire thing
> into my solvent tank for a couple days before taking it apart as far
> as possible, cleaning, re-assembling, lubricating, and re-installing
> it into the transmission.
>
> Just out of curiosity, I swapped this transmission into my '99 Forry
> (I needed to service the clutch anyway), where it appears to be
> working just fine. Haven't put but about 1000 miles on it yet, tho, so
> time will tell.
>
> In any event, because of where the center diff lives (at the back of
> the transmission in it's own chamber), it doesn't appear to get much
> fluid circulation. This suggests to me that frequent fluid changes in
> the transmission are probably indicated, and may well prevent the
> viscous coupling from becoming gummed up.
It is my understanding that the "viscous coupling" part of central
diff is a sealed unit, and its fluid is never replaceable. Only the
outer gearing of the central diff gets lubed by transmission oil in
the normal way.
Yousuf Khan
S
On Tue, 6 Oct 2009 09:23:04 -0700 (PDT), XR650L_Dave
<spamT...@yahoo.com> wrote:
>I believe the center diff viscous coupling is sealed from the
>transmission fluid, so changing the trans fluid will not have any
>effect on manual-transmission torque bind.
Lightning McQueen: "What are you talking about?"
Mater: "I dunno."
I was gonna say "The center differential lives in the same fluid as
the gear train . . ." But when I thought about it, there was an O-ring
. . .
So I looked back thru some fotos I took after I disassembled the
center diff/viscous coupling.
Darn it, Dave, that VC was a sealed unit. Wonder why I didn't notice
that; sometimes I'm kinda slow :-P
Anyway, 'taint no mo; it's been reworked with good ol' 90WT in place
of the silicone. What's the saying? "A little knowledge is a dangerous
tool."
Wonder if I should put the original transmission back in now, or wait
'til it fails on the snowiest day of the season? Sigh.
Er, um, Yousuf, a.a.s gang, please ignore the part about flushing the
transmission; as Dave suggests, it won't do a bit of good.
If anyone's curious what the internals of one of these things looks
like, email me directly and I'll send along a couple of fotos.
XR650L_Dave
> Hi Dave!
>
> On Tue, 6 Oct 2009 09:23:04 -0700 (PDT), XR650L_Dave
>
It wont fail, you just have slightly less-good AWD.
Now too bad we didn't know just what the fluid was, you could just
clean 'em and refill 'em.
Dave
Dave
YKhan
> I did recently change the tires on this thing, about a month back, but
> they are all brand new and exactly the same model. I'll see if there
> is a tire pressure difference somewhere.
>
> Yousuf Khan
Just an update, after I checked the tire pressures, I did notice that
one of the tires (the left front) was about 3 psi higher than the
other three, so I've adjusted that one down to the same level as the
others. So far, it seems to be shuddering a bit less. Not totally
stopped shuddering, just not as much as before. Maybe it takes a bit
of time to settle down.
It's interesting, in the past I've had air leak problems on my tires
where after a couple of months, some of the tires may have lost more
pressure than the difference I've seen here, but it never resulted in
a shudder until now.
Yousuf Khan
Chico
My 2003 OBS 5sp center diff went around 150,000kms. Same symptoms:
parking maneuvers caused a shudder - almost a clunking that goes with
the speed of travel. It happens in neutral, so it's not gear
related. And it happened only once the car was warmed up. That's
what tipped me off. A 10 minute drive down the highway was enough to
warm things up, and then I couldn't park without the shudder.
The dealer scared me into doing it right away by telling me that the
expensive transmission could eventually get damaged by leaving the
diff alone. $1600 or something like that.
All is well now, 50k kms later.
1 Lucky Texan
I've read 'rumors' that making figure 8s/tight maneuvers IN REVERSE
can alleviate some center diff symptoms.
I've never tried it and it seems weird.
I think I've seen pics/article on-line where some Aussies are
disassembling the center diffs and replacing the fluid to make them
engage more quickly for some kinda off-road use. So, maybe it IS
possible to rebuild one?
good luck (don't forget to check the U joint on the driveshaft)
Yousuf Khan
> My 2003 OBS 5sp center diff went around 150,000kms. Same symptoms:
> parking maneuvers caused a shudder - almost a clunking that goes with
> the speed of travel. It happens in neutral, so it's not gear
> related. And it happened only once the car was warmed up. That's
> what tipped me off. A 10 minute drive down the highway was enough to
> warm things up, and then I couldn't park without the shudder.
>
> The dealer scared me into doing it right away by telling me that the
> expensive transmission could eventually get damaged by leaving the
> diff alone. $1600 or something like that.
>
> All is well now, 50k kms later.
Ouch! So far, it doesn't happen in neutral yet. And it's unrelated to
how warm the transmission is: it'll happen warm or cold. So I'm hoping
that this means that mine is not as serious as what happened to you.
I'm still investigating the tire inflation pressures to see if they make
it go away. I've never had to worry about the tire inflation tolerances
this much before. Usually I could keep the tires within 2 psi of each
other.
Yousuf Khan
Yousuf Khan
> I've read 'rumors' that making figure 8s/tight maneuvers IN REVERSE
> can alleviate some center diff symptoms.
>
> I've never tried it and it seems weird.
Yeah, that does sound weird. Can't see why that should work, but I'll
keep it in mind.
> I think I've seen pics/article on-line where some Aussies are
> disassembling the center diffs and replacing the fluid to make them
> engage more quickly for some kinda off-road use. So, maybe it IS
> possible to rebuild one?
>
> good luck (don't forget to check the U joint on the driveshaft)
Well, I'll play with the tire pressures some more. Maybe these tires are
just more sensitive to tire inflation than any of my previous set?
Yousuf Khan
XR650L_Dave
"S" on this thread said he took his apart and drained the fluid (which
leaves you with slightly less good AWD), so if you had the fluid to
put in (a bucket of it so you could re-assemble the viscous-clutch
unit submerged) you'd be able to rebuild your own.
Dave
.._..
is that the "stick" gauges absolutly suck balls.
Get a "dial and needle" type for a few bucks more. (Which should still be
under 20). Then use a sample of five or six tests to get a reading.
"Yousuf Khan" <bbb...@spammenot.yahoo.com> wrote in message
news:4ace12b3$1...@news.bnb-lp.com...
Yousuf Khan
> One thing I learned while dealing with the torque bind due to tire pressure
> is that the "stick" gauges absolutly suck balls.
>
> Get a "dial and needle" type for a few bucks more. (Which should still be
> under 20). Then use a sample of five or six tests to get a reading.
I got a dial'n'needle, but I also got a digital unit, which reads out in
increments of 0.5 psi.
Yousuf Khan
Yousuf Khan
> If anyone's curious what the internals of one of these things looks
> like, email me directly and I'll send along a couple of fotos.
>
> ByeBye! S.
> Steve Jernigan KG0MB
Thanks for sending the pix of the viscous coupler. It definitely didn't
look like what I had imagined. I was imagining the VC was similar to the
torque converter VC that they use inside automatic transmissions, which
is basically an impeller-propeller assembly. This thing is nothing at
all like a torque converter, and now I have a better picture in my head
about it.
Yousuf Khan
Gilbert Smith
I have got exactly these symptoms on my 2005 Forester 2.0 XT after
only 20k miles. The dealer says it needs a new rear axle for 3k pounds
but it feels more central to me so I will have to get a second
opinion. I like the reversing idea, I only tried figure 8s forwards on
grass.
Changing the oil/fluid etc, shuffling/inflating the tyres makes
absolutely no dirfference. Carrying a heavy load makes it much worse,
presumably because the wheels cannot slip on the tarmac so easily.
S
On Wed, 7 Oct 2009 09:05:41 -0700 (PDT), XR650L_Dave
<spamT...@yahoo.com> wrote:
>Now too bad we didn't know just what the fluid was, you could just
>clean 'em and refill 'em.
Actually, the thought crossed my mind. The fluid viscosity is the
obvious variable affecting VC performance, at least over the near
term, with shear resistance governing it's long term outlook.
Funky weather over the weekend prevented me from swapping
transmissions (Sat, Sun, never got above 22F, with a little snow and
freezing mist mixed in; hello . . . still October . . .), but as soon
as the weather co-operates I'm going to do so. Gonna need that AWD
soon by all indications.
At some point I will pull and clean the bad CD again, and then see if
I can some of our Mechanical Engineering/SAE types involved. (They owe
me anyway :-)
Well beyond what little I remember from Classical Mechanics in college
(been a long time; we were still using slide rules), but probable that
a sharp ME can calculate viscosity requirements based upon the VC
design, and engine HP.
If this leads anywhere, you guys 'll be the first to know.
Yousuf Khan
the other day, and we found out what the problem is. The power steering
fluid is leaking out, and it's because the rubber seals have cracked on
the assembly. The dealer is suggesting that I totally replace the entire
steering rack assembly. He is saying that there is no fix for just the
seals alone, the whole rack has to be replaced!
Is this true, or is he just blowing smoke up my ...? Replacing the
steering rack will cost $1100 including labour, he says.
I was thinking of just topping up the power steering fluid as a
temporary fix.
Yousuf Khan
weelliott
>
> - Show quoted text -
Replacing the rack yourself is not that hard, and would save you
hundreds of dollars. If weather won't allow this, then just keep
topping it off until spring rolls around. I did mine in about four
hours without really knowing what I was doing prior to getting the
rack. I think knowing now what I knew then, and being more familiar
with the area, I could do it in two or so hours. I used a haynes
manual and this site:
http://www.tomorrowstechnician.com/Article/648/undercover__straight_talk_on_subaru_steering_service.aspx
It says to disconnect the tierod ends at the steering knuckle. I
unthreaded them instead of popping them out. It does screw up the
alignment, but I think it was much easier than popping the ends out,
and I didn't want to chance destroying them with a tierod end puller.
I tink I paid about 245 for the rack and another 17 bucks each for the
boots, and I replaced the inner tie rod ends while I had it apart.
Actually, I don't remember if I did the boots on that car, or my other
subaru. The rack might have come with them.
Good luck.
S
On Mon, 26 Oct 2009 06:10:09 -0700 (PDT), weelliott
<weel...@gmail.com> wrote:
>Replacing the rack yourself is not that hard, and would save you
>hundreds of dollars. If weather won't allow this, then just keep
>topping it off until spring rolls around. I did mine in about four
>hours without really knowing what I was doing prior to getting the
>rack. I think knowing now what I knew then, and being more familiar
>with the area, I could do it in two or so hours. I used a haynes
>manual and this site:
>http://www.tomorrowstechnician.com/Article/648/undercover__straight_talk_on_subaru_steering_service.aspx
>It says to disconnect the tierod ends at the steering knuckle. I
>unthreaded them instead of popping them out. It does screw up the
>alignment, but I think it was much easier than popping the ends out,
>and I didn't want to chance destroying them with a tierod end puller.
>I tink I paid about 245 for the rack and another 17 bucks each for the
>boots, and I replaced the inner tie rod ends while I had it apart.
>Actually, I don't remember if I did the boots on that car, or my other
>subaru. The rack might have come with them.
>
>Good luck.
FWIW, you can almost always loosen tie rod ends using the following
procedure, and it doesn't disturb the alignment settings.
1) Remove the cotter pin, and loosen the nut. Thread the nut back on
with the crenelations down, such that the bottom of the nut is flush
with the top of the threaded part of the tie rod.
2) Place the flat head of a ball pean hammer against the nut/tie rod,
and give it (the hammer head) a sharp wack with a second hammer.
Usually, the taper will pop right out.
The heavier the second hammer is, the better this works. You don't
really need the first hammer, if you have good aim, but if you fail to
hit the nut squarely, you may damage the nut/threads.
I don't recall there being any thing else particularly difficult in
removing/replacing the steering rack, except that they are usually
pretty greasy/dirty (hit the area with some Gunk before hand), and
there may have been a couple of the fasteners that were challenging to
access. An air impact with swivel sockets is your friend.
Another thing, if you _do_ have to disturb the alignment, either thru
removal of a tie rod or whatever, you can put it back pretty close by
taking careful measurements from the center of the back of the tie rod
to where the threads enter the link, and also center to center across
the rack. Duplicate these numbers when you reassemble.
YKhan
> Replacing the rack yourself is not that hard, and would save you
> hundreds of dollars. If weather won't allow this, then just keep
> topping it off until spring rolls around.
Looks like that's going to be my solution for now. In another thread I
have now mentioned that it looks like the shudder had absolutely
nothing to do with my steering mechanism, it was caused by a loose
cracked exhaust pipe. Once that pipe was replaced, the shuddering just
stopped. So even though the power steering fluid is leaking out, it
doesn't look like it was as bad as I thought.
Yousuf Khan
S
Yea, I wouldn't tackle the rack job unless/until:
1) The leaking fluid was making an intolerable mess, getting on the
exhaust and causing a stink, whatever, or
2) It was leaking to the point where you couldn't keep up with it by
topping off the reservoir when you do a fuel fill-up more or less.
Power steering fluid is cheap; manual labor isn't :-)
ByeBye! S.
On Tue, 27 Oct 2009 22:13:38 -0700 (PDT), YKhan <yjk...@gmail.com>
wrote:with
Steve Jernigan KG0MB
Gilbert Smith
Any chance you were heating up the center diff with the exhaust leak ?
This low speed turn shudder is typical of the viscous coupling getting
tight.
aguir...@yahoo.com
the tire pressure theory sounds preposterous as racers use different air pressures on tracks all the time.
Yousuf Khan
> My 05 XT shudders at parking lot speed while turning, doesnt seem to
> do it at all in reverse and its an automatic transmission so it may
> be a separate issue than what yousef has been having but its
> similar.
anymore. However, as I recall, the problem turned out be a leaking power
steering fluid pump.
> the tire pressure theory sounds preposterous as racers use different
> air pressures on tracks all the time.
4WD like Subarus. Racers are by and large, 2WD vehicles. Since there are
at least 3 differentials and stuff in Subarus, that tire pressure
differentials between front and back will get noticed.
However, this was not the problem in my previous vehicle's case, it was
the power steering failing that caused it.
Yousuf Khan
4orester
springs that normally open to let the inner and outer rotations differ
during turns are stiff and causing the valves to bind. I fixed mine and
there's 2 solutions. You can get a kit which replaces the springs with
lighter ones ($$$$$) OR, here's the best one, get some Seafoam transmission
oil treatment and change the oil in the differentials. The whole service
cost me about $150 and it worked like a charm. That was over 6 yearrs ago
and I've had no issues since. Cheap and VERY effective.
If you do some research online you will find others who did the same thing
with the same results. I still have my 04 - its a little tank.
<aguir...@yahoo.com> wrote in message
news:f233d7fb-a8d4-47e3...@googlegroups.com...
Piso Mojado
Mitsubishi that was fixed by adding a few ounces of an extra slippery
additive in a tube from NAPA to the differential case.
--
That we're even debating whether boys who think they're girls ought to
be able to shower with the girls signals society in collapse.
- @EdWhelanEPPC
bikesing...@gmail.com
> Usually it's air pressure in the tires.
>
> "1 Lucky Texan" <alck...@swbell.net> wrote in message
> news:b12d960b-7316-4e61...@p36g2000vbn.googlegroups.com...
> > My 2000 OBW w/ 5MT has recently developed a slight shudder during sharp
> > cornering at low speeds. I'm talking about parking maneuver type
> > situations. It seems to occur whether I'm turning left or right, just as
> > long as it's slow and sharp.
> >
> > I've seen this type of shuddering before on this car, but those were
> > during cold winter days when there was a bit of ice that built up on the
> > joints, and they go away if you let the ice melt away. But it's nowhere
> > near winter yet, and there isn't a flake of snow on the ground right now.
> >
> > What could this be? CV joints, or differentials (i.e. front to rear)?
> >
> > Yousuf Khan
>
> lucky, if not - center diff.
>
> Some folks have found bad U joints on the drive shaft.
>
> Carl
I googled this problem which kept getting worse (winter time). A month ago I had checked my air pressure and one back and one front were about 22 lbs. So when I saw this guy's post on air pressure, I felt like a fool, checked my air again and one front tire was at 11 pounds. I drove away after airing up and bingo, all is perfect again. Thanks to this guy that posted, Google, and smart phones. I was about to spend hundreds or possibly thousands to have it repaired. Jim