Shudder at very low speed during sharp turning

[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]

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.

 

[S]

Hi Dave, All!

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.

ByeBye! S.

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

 

[Yousuf Khan]

Here's an update on my problem. Finally got it over to the dealership
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]

Here's an update on my problem. Finally got it over to the dealership
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






- 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/...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]

Hi Yousuf, Weelliot!

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/...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.

ByeBye! S.

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

 

[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]

Hi Yousuf!

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.

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

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

 

[Gilbert Smith]

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

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.