Forester Is my Viscous Center Differential (VCD) faulty?

Palm12

Palm12

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Thread starter
Joined
Jan 18, 2021
Messages
3
Location
Denmark
Car Year
2009
Car Model
Forester
Transmission
Manual, with low range
Car: Forester SH, Non-turbo 2.0 with a manual transmission, and dual range gear box. 155,000 km/ 96,000 miles.

When I tried to turn around on a bad dirt road I ended up with the right front wheel in the air and the left rear wheel almost without grib. The vcd did’nt send power to the right rear which had fine contact or the left front which also had contact, however down in a ditch / hole

I was stuck and was not able to get myself moving again. I had to be pulled out by a Nissan Patrol 😩

Well, If one wheel loses traction, the viscous coupling should sends power to the wheels with more traction. Why did’nt it?

I've figured out that an explanation might be that the VCD is really only able to send torque to the front axle or the rear axle, not sideways. Or is it faulty?
 
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:welcome: to the forum.

More likely that your rear vLSD is knackered, if anything at all is not functioning properly. The centre vLSD can be destroyed by doing even one or two donuts, but that is highly unlikely in a 2 litre SH, as it just doesn't have enough power or torque to even do that. More common problem with WRXs.

Did you have VDC (vehicle dynamics control) on or off at the time.

BTW, no AWD or 4WD system is 'perfect', specially not the 'on demand' AWD systems found in most supposedly AWD vehicle brands. There is no magic bullet. Many (most?) strandings are due to the particular situation, or often operator error or inexperience.

You can bog a Landcruiser (easily ... ). They do not like soft surfaces at all. I speak from experience.
 
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Thanks a lot for replying.
I tried to get out with both the VDC (in my car the button is called ESP - Electronic Stability Program) on and off.
You’re right, no donuts done in a 2 litre SH 😊
@ateday, no uneven tyre wear eigther.

Maybe it was just the particular situation, and the fact that I dont have a lot of experience.

Is it possible to test if the LSD/VCD is fine by doing a roller test? Like this one
or are all vids like this manipulated?
 
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Sounds like your centre diff is working just fine as it can only transmit power to the front or rear diff, it’s up to the front and rear diffs to determine which wheels it sends power to that it receives from the centre diff.

I’m not up with the SH model specs, being a 2L it may not have a vlsd in the rear, it could just be an open rear diff, which could explain what you experienced.

Cheers

Bennie
 
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@El_Freddo Bennie, our 2.5L 2009 SH 4EAT sports auto has a vLSD in the back, so it's unlikely to be missing from a dual range manual model. But who knows? Check the owner's manual specs perhaps?
 
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@ateday Exactly. However, I doubt that they would change the rear diff, when a vLSD has been standard on all Foresters since about 2002, including my wife's 2009 SH.
 
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Ratbag said:
@ateday Exactly. However, I doubt that they would change the rear diff, when a vLSD has been standard on all Foresters since about 2002, including my wife's 2009 SH.
Click to expand...
In Australia yes. But as @ateday says, it’s the European market and many things can be different for their market and what the European department of Subaru wanted to offer in their models. Otherwise there wouldn’t be a JDM, AUDM, USDM etc.

Cheers

Bennie
 
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The vLSD aint broke cause it aint there. (reminds me of Tarantino as Jimmie in Pulp Fiction). I spoke with my local Subaru dealer. On my model (standard in Europe) its an open diff. The viscous diff is only on the XT models. Your were unfourtunatly right😥
I have seen an old thread about various after market opportunities. https://www.subaruforester.org/threads/differential-lock-upgrade.64343/
Does anyone have recommendations?
 
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