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VTD Multi plate center diff DEMO

10695 Views 17 Replies 5 Participants Last post by  lame_dc
I just finished swapping in my 02 Forester 4EAT a VTD multi plate center diff from a 02 4EAT WRX donor.

Initial impressions.
The characteristics remind me of the 5spd AWD setup. The reason I say this is because of the wandering it has up front when you apply throttle. The VLSD center diff on the 5spds aren't the best in keeping the front and rear tight. The lockup is "enough" but not enough in my opinion. So in comparison without any hydraulic pressure utilizing the multi plate clutches of the VTD differential, it operates as an open differential.

The clutch plates are 2 less than your transfer clutch units (3 vs 5). I hope that the differential action does somewhat help. I will have to test how well it holds up in dirt/rock climbing situations where wheel slippage is minimized.

Now it's hard to tell the rear biased because I have a welded differential in the rear. It's also snowing in MN right now. The rear end does step out when I give it throttle, however the welded diff plays a big part in that. I would say it is feeding as much as it can since the rear does come out when I don't have the clutch plates engaged via my switch.


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The Forester 4eat uses a transfer clutch to drive the rear. The WRX 4eat uses a planetary gear center diff with a torque split off 45:55 and transfer clutch to lockup for maximum front/rear traction. I like the center diff more than the transfer clutches driving the rear. This functions just like the DCCD. I wished it was standard on all Subaru manuals and autos. The VLSD sucks.

Here's a test on frozen dirt going up a mound

I was reading through your swap and the limited info out before doing mine. Thank you for providing some details on your setup!

While the OEM transfer clutch was nice, it was slipping on me when I took it off roading in TX with the welded rear. It was holding but not enough when going up hill. The rear relied on the plates friction to push the car forward. Then again the tranny also had 200k miles.

Here the original transfer clutch doing work.
I had the locking mod, but the tranny had like 200k miles. A bit worn on the transfer clutches perhaps.
I'll take a picture of them later.
Here are the plates from my 02 Fozzy's transfer clutch. There are some material on the plates. Seems the plates got glazed from the clutch material.

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A new video running through packed snow. Using light throttle to minimize excessive wheel spin.

Added 1 more disc and plate. Now 4 instead of 3 discs.

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I pulled out one of the thick rings. I picked up another VTD tranny from a baja XT and used a disc/plate from that.

How were you able to add 1 disc ? Did you put narrower bearings ?
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