Hi all,
I'm a long time 4wd'r however only just bought my first Subaru (Forester x auto 07) and loving it. i have a question re the drivetrain. I took off on gravel the other day and the front wheels broke traction before the car gained grip and took off and then again yesterday on a wet rd the front broke traction again. I have taken the car offroad and the 4wd seems to be working as i was able to crawl up a reasonably steep muddy hill and cross some deep ruts which i'm positive that i would'nt be able to do otherwise. however the front braking traction is puzzling me, can someone tell me if this is normal??
Cheers Richo
Traction
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Gannon
- Senior Member
- Posts: 4580
- Joined: Sat Nov 05, 2005 10:00 am
- Location: Bowraville, Mid Nth Coast, NSW
Most Subaru auto transmissions dont have a centre diff, only the turbo models do.
What your car has is a MPT (multi plate transfer) clutch that powers the rear wheels, the fronts are always connected.
So in normal driving, about 15% of the engine torque is available at the rear wheels because the MPT is defult about 30% locked.
The harder you push your foot down, the more the TCU (transmission control unit) locks the MPT, up to about 90% or 45 to the rear wheels.
If the TCU detects wheel spin, it also ramps up the MPT to prevent it, but there is a slight delay, so the front wheels spin a little.
Dont worry they all do it.
What your car has is a MPT (multi plate transfer) clutch that powers the rear wheels, the fronts are always connected.
So in normal driving, about 15% of the engine torque is available at the rear wheels because the MPT is defult about 30% locked.
The harder you push your foot down, the more the TCU (transmission control unit) locks the MPT, up to about 90% or 45 to the rear wheels.
If the TCU detects wheel spin, it also ramps up the MPT to prevent it, but there is a slight delay, so the front wheels spin a little.
Dont worry they all do it.
Current rides: 2016 Mitsubishi Triton GLS & 2004 Forester X
Ongoing Project/Toy: 1987 RX Turbo EA82T, Speeduino ECU, Coil-pack ignition, 440cc Injectors, KONI adjustale front struts, Hybrid L Series/ Liberty AWD 5sp
Past rides: 92 L series turbo converted wagon, 83 Leone GL Sedan, 2004 Liberty GT Sedan & 2001 Outback
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Ongoing Project/Toy: 1987 RX Turbo EA82T, Speeduino ECU, Coil-pack ignition, 440cc Injectors, KONI adjustale front struts, Hybrid L Series/ Liberty AWD 5sp
Past rides: 92 L series turbo converted wagon, 83 Leone GL Sedan, 2004 Liberty GT Sedan & 2001 Outback
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