Shudder at very low speed during sharp turning

#11

On Oct 7, 11:06*am, S <jerni... (AT) chester (DOT) uccs.edu> wrote:

Quote:

Hi Dave!

On Tue, 6 Oct 2009 09:23:04 -0700 (PDT), XR650L_Dave

spamTHIS... (AT) yahoo (DOT) 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.

ByeBye! S.
Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101

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

#12

On Oct 6, 12:56*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

Quote:

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

#13

On Oct 5, 9:36*pm, Yousuf Khan <bbb... (AT) yahoo (DOT) com> wrote:

Quote:

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

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.

#14

On Oct 7, 5:29*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

Quote:

On Oct 6, 12:56*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

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

I've read 'rumors' that making figure *s/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)

#15

On Oct 7, 5:29*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

Quote:

On Oct 6, 12:56*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

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

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)

#16

Chico wrote:

Quote:

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

#17

1 Lucky Texan wrote:

Quote:

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.

Quote:

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

#18

On Oct 8, 12:07*pm, 1 Lucky Texan <alcky... (AT) swbell (DOT) net> wrote:

Quote:

On Oct 7, 5:29*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

On Oct 6, 12:56*pm, YKhan <yjk... (AT) gmail (DOT) com> wrote:

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

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)

"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

#19

S wrote:

Quote:

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

#20

Chico <chicobiker (AT) yahoo (DOT) com> wrote:

Quote:

On Oct 5, 9:36*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

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.

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.