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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #1
So if the front diff pinion bearings are getting noisy, any thoughts on if there is any lube or additive choice that can stretch out the time to repair?
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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15,483 Posts
You are having the worst luck with this car.

You could try a Lucas additive. How bad is it?
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #3
Just shy 200,000 miles so some things are bound to happen, with plenty of full-throttle romps and the occasional run up to max speed taken into account...

The noise isn't that bad now, but it is progressing.

Front diff fluid has always looked and smelled fine, has even been changed on occasion.

There's no such thing as magic goo in a bottle, but sometimes the right stuff can stretch it out.
 

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'03 Outback H6-3.0 Black Granite Pearl, base model with cold weather package and cloth seats.
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1,072 Posts
Mine went at 225k miles.

First, check the magnetic drain plug for metal. If there are chunks, not dust, you have a problem.

The heavy Lucas additives can slightly delay the inevitable....

I ended up with a Subaru-rebuilt tranny/front diff assembly......
 

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2011 Tacoma TRD Sport Double Cab Long Box
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2,893 Posts
Just shy 200,000 miles so some things are bound to happen, with plenty of full-throttle romps and the occasional run up to max speed taken into account...

The noise isn't that bad now, but it is progressing.

Front diff fluid has always looked and smelled fine, has even been changed on occasion.

There's no such thing as magic goo in a bottle, but sometimes the right stuff can stretch it out.
Can't offer much input on the diff--I think if anything my rear would be the first to go. What is max speed on an '03 Bean? I've always been curious where they're governed. I heard 124 but don't know how accurate it is.
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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I haven't found out yet, either. Been to 122 with plenty of room to 7k and another gear to go.

The Trans has to come out for any diff repair, so rebuilding the trans while its out is a good idea. When you get to, have the shift kit available and add in a large trans cooler.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #7
I've changed out the front fluid for lucas with 50% lucas additive, no change in the noise.

Took the crud off the magnet, the flakes here are incredibly thin and might just be tiny particles held together because they are magnetized, no solid pieces at all.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #8
posted a vid of the noise, the persistent rumble is a wheel bearing, pinion noise is the one that comes and goes as I add/reduce throttle.

 

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'03 Outback H6-3.0 Black Granite Pearl, base model with cold weather package and cloth seats.
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1,072 Posts
I would guess anything larger than dust qualifies as chunks. Any small pieces coming loose would likely end up going thru the gears and getting flattened. Possibly further damaging the gear surfaces.

The noise coming/going during throttle (load) on/off is consistent with my failure.

After a certain point, the heavy Lucas oil no longer made a difference in the noise level.
 

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'03 Outback H6-3.0 Black Granite Pearl, base model with cold weather package and cloth seats.
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1,072 Posts
OH, and

Welcome to the Noisy Front Diff Club!

There is a bullet to be bitten here.....
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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15,483 Posts
Dave, that sounds bad. Hard to tell exactly, but seems like bearings or loose pinions.
 

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'99 Outback 2.5 GT auto & '97 LegOB w/ grossly insulted 2.5
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141 Posts
The shiny portion of the debris reminds me of British motorcycle gear boxes I have failed. I wrote those off to poor under-surface gear hardness. With the ability of these cars to handle slippery conditions; could transitions between spinning & high traction be exceeding the robustness of the differential pinions? Have a '57 Chevy that wheel-hopped & broke these gears until heavier rear spring main leaves stopped the wheel-hop. I've considered all pinions with a prejudiced eye ever since.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #13
The lucas didn't change the noise, and it hasn't gotten worse... yet...

I've been careful to not spin the tires when transitioning from low traction areas to high traction areas. I did in a worn '92 ranger drive shaft that way once...

Noise started over the summer.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #14
Noise with rear wheels on the ground and not moving:


I think this is definitive, front pinion bearing.

I also confirmed even in 1, there is NO drive to the rear wheels until you step on the gas (whern I had all 4 off the ground, heh)
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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15,483 Posts
Noise with rear wheels on the ground and not moving:

Bad front pinion - YouTube

I think this is definitive, front pinion bearing.

I also confirmed even in 1, there is NO drive to the rear wheels until you step on the gas (whern I had all 4 off the ground, heh)
That's because your LL Bean uses the MPC and is predominately FWD.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #16
Yeah, 90% FWD until something slips, but 1, 2, and R make it much more evenly split as soon as slippage occurs.

There was controversy, though, about when you put it in 1, 2 or R if it was 'locked' into 50/50 (MPT as engaged as it ever gets, anyway) or if slippage had to be detected first.

Even so, it was much quicker to drive the rears in 1 than in D, so 1 is certainly better for grip than D.
 

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We covered this in quite some detail in the FreeSSM thread. Lots of data on where the AWD control duty cycle signal is under different conditions.

The control responds not only to slip, but to risk of slip represented by throttle position, engine torque, wheel speed, gear etc. You don't need any wheel slip to see the control go from the base level of around 30% duty cycle (which in itself is significant) way up to 90% or more based only on throttle position. That's what distinguishes the Subaru full-time AWD from other makes that are in fact FWD until slip is detected and then they go switch to AWD (it's either on or off, without anything in between as with the Subaru.)

In 1st gear, the rate at which the duty cycle responds to factors other than actual wheel speed differences (aka slip) is faster than in the higher gears, but that corresponds to the fact that torque to the wheels in the higher gears isn't as great as in the lower gears, so the risk of breaking traction in the lower gears is higher.

It's a fascinating and very responsive system when it's working.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #18
Trans is in the hatch, $860, 96k on it, out of a 2004 LL bean.

Came with the converter and I asked them to leave the mounts on.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Discussion Starter #19
On the way home last night I thought I may have smelled gear lube.

Pulled the car in the garage last night, am starting the trans swap.

There's oil under the car.

I'm goin' in.
 
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