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Shudder at very low speed during sharp turning
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Shudder at very low speed during sharp turning -
10-05-2009
, 09:36 PM
#2
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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
#3
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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
#4
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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)? |
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
#5
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Hi Yousuf! On Mon, 05 Oct 2009 21:36:50 -0400, Yousuf Khan <bbb... (AT) yahoo (DOT) 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. 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 |
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
#6
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On Oct 5, 8:36*pm, Yousuf Khan <bbb... (AT) yahoo (DOT) 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)? * * * * Yousuf Khan d@mn - most likely 'torque bind' . From mis-matched tires if you're lucky, if not - center diff. |
they are all brand new and exactly the same model. I'll see if there
is a tire pressure difference somewhere.
Yousuf Khan
#7
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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 |
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.
#8
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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. |
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
#9
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Hi Yousuf! On Mon, 05 Oct 2009 21:36:50 -0400, Yousuf Khan <bbb... (AT) yahoo (DOT) 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. |
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.
Quote:
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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. |
the same unit, so they both get changed at the same time. I think the
rear diff was also done at the same time.
Quote:
|
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". |
Quote:
|
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. |
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
#10
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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. |
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.
ByeBye! S.
Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101
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