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2003 Outback VDC 3.0L H6
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10 Posts
Discussion Starter #1
I've noticed over time since I got the car at 113k miles on it (now at 160k) that it has always had the rev-bang from 4-3 downshift most of the time. I usually drive it like a 90 year old lady as I have another car for beating on. The car sees 85% of it's milage on the highway as I do a lot of long distance traveling.

Along with that I've had times doesn't downshift at all when I floor the peddle. The trans simply ignores my input and goes about it's buisness.

Another issue I'm having (far more irritating than the others as I've learned to drive it without issue) is when I'm going up a steep incline like the ones in Gatlinburg TN. If I'm doing about 15-20mph climbing gradually the TC will lock and unlock rapidly, jerking like ****. So I either let off the gas or give it more throttle to stop it. But as soon as I hold my position, it starts jerking again. It does it regardless if it's in 2nd gear lockout or drive.

Things I've done are the regular fluid services though Subaru and at home as per the manual.

I've replaced the TP sensor with one from AutoZone after hearing about a tsb for it. But I'm not sure if that was a good move. It was done about 3years ago. (Considering saying screw it and getting oem)

Replaced center driveshaft with a custom made unit as well as both front CV axles with Subaru remans from the dealership.

And I have new rear diff bushings on the way.

No codes, or anything warning wise according to my chepo $40 scan tool.

Before I pay Subaru to diagnose, does anyone have experience with this behavior?
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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26,479 Posts
if it turns out you need a trans: 2001-2003 VDC outback, or 2004 VDC outback with some electical parts swapped

or a JDM for the 212hp H6 = in their years this is a 1999-02,..all those 212hp H6 engines there were VDC trans.

(and not any oddball WRX, or other 4EAT, or the later 5EAT.)
 
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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
Joined
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26,479 Posts
you could try hooking a windows laptop to it with Free Rom-Raider that logs, this year can also take FreeSSM.

just need a $10 VAG cable. (a USB cable that hooks to the ODBC port).
 
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Premium Member
2001 VDC/SC One of a Kind
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14,762 Posts
If I understand you correctly, when in 2nd gear hold, the car jerks?
Yes, bad move with the AutoCrap part.
The VTD has a multiplate clutch that is applied to give you a 50/50 torque split front/rear. When it is not applied, you have 45/55 split. It may be the VTD clutch/planetary gears you are hearing. Under load, and higher engine rpm, the transmission line pressure increases and this will add speed in apply and piston pressure on the clutches. You could have a bad ground or a failing solenoid for the VTD clutch. The torque converter only applies in gear selector 3 or D when the car is cruising or if the VDC is active and the computer is using the TCC to effectively control traction in emergency stopping situations as it downshifts the transmission. I've never experienced a TCC lock in 2, and I've done 2nd gear pulls to 80, or so, in 2. No TCC lock.

I doubt its an issue that will require replacement of the transmission. Its going to be electrical in nature, like the grounding or a solenoid. Could even be the transmission mount causing the noise. As for the rev-bang, I get that sometimes out of nowhere and have yet to determine the exact cause. Its done it since I've had the car, even before the SC. I think it is a 4-2 downshift that is causing the bang and not a 4-3. The TCM is releasing the TCC and downshifting at the same time which causes a severe torque transfer to take place, especially if going 4-2, and the ratio change and high torque is the cause behind the bang effect.

The other thing you mention about the "lugging" and not downshifting is another anomaly that the only thing I can come up with is its in the ROMs of the ECM and TCM. Depending on your speed and the engine load calculated by the the ECM, the TCM will keep the transmission in higher gear ratios to reduce emissions and keep engine performance steady. The back and forth shifting is where the calculating comes in. The engine load is calculated from the inputs - TPS, MAP, RPM, Temp and Gear. My car cruises at 10% load. It holds 4 w/TCC lock going up hill. It seems like it is lugging, but really its only running at about 30% load when I think its lugging.

Here's my suggestion: Since you have regularly flushed the transmission, clean the grounds, check the ampere output of your battery and conductance after cleaning the grounds. Your scan tool can't clear the TCM and reset it, so when you clean the ground cable the disconnect from the battery will reset the TCM memory. This will force the TCM to relearn shift patterns and create a new shift map based on your driving. It's adaptive programming - It "learns" based on set values in the ROM. It may still do the "lugging", but it may change its map for the downshift and start shifting smoother. Usually it learns pretty quick, within 100 miles and then it becomes fixed.

On the rear diff bushings - I used Window Weld in my rear diff bushings and it has remained solid since I put it in. And its like installing neoprene as far as rigidity. The car just has to sit still for 24 hours after you "build" your bushing.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,938 Posts
General note on the Gen2 H6 cars- wiping the learning by disconnecting the battery can significantly ease the 4-3 hard downshift for weeks to months.
 

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Registered
2003 Outback VDC 3.0L H6
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10 Posts
Discussion Starter #6
lol first I appologise as I havn't had the chance to get on here to view the thread in a rather long while. Ive been super busy with the new house and life in general. I still have my OB and its at 174k now. I've gotten used to the trans and just drive it in a way that keeps it happy. I will definitly clean up the grounds and see what happens.

I'm in agreement that what I'm feeling is the 4-2 downshift. If i manually go from D to 3 doing speeds above 50ish, it doesn't have any issues at all. Then once its fully in 3rd I can step on it and it will go. If I'm slower it will kick down to 2nd. But I found in any situation I have to press the gas in a quick sense to get it to do so. I'm planning on hitting the salvage yard this weekend as they have a great looking ****** I wouldn't mind getting a few spare parts off of.

Since I started the thread, I figured I'd give some info. Ive had to replace the alternator and battery so far since then. And I'm currently dealing with an odd shimmy that is felt throught the car and shakes the steering wheel pretty good. If I'm using super light throttle the rear diff howls and a short time later the steering wheel shakes rather crazy. Once i'm back on the gas it goes away. Its strongest at around 70mph.

So I was going to look into a new rear diff as both wheel bearings have been replaced already within the past couple months with timkins.

I have a small question. After reading various forums, I kind of feel stupid as I can't seam to understand clear enough what exact years, models, and trims of subarus I can take use a rear diff out of. If I understand I got that I have a R160 Open diff with 4.11 ratio. Knowing I have a VDC model, what would be the downfall to installing a rear diff from an LL Bean?

I apologise in advance if theres a forum that has already had these questions answered. I'm just having an issue comprehending it for some reason. And yet I was able to tune my miata on a new ecu without issue.
 

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Premium Member
2001 VDC/SC One of a Kind
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14,762 Posts
Check your tire pressures. The shaking could be a low tire. AWD has to have identical tires at all 4 wheels and pressure makes a difference in the wheel rotation. Another thing is to check the axles again; rear bushings on the front lower control arms; hanging up brake caliper on one of the wheels is a possibility.

As for the diff - regardless of VDC or LL Bean, the diff is geared the same in both H6 models. It's the H4 and the Legacy platform (non-Outback) that you have to watch for. Different years and models had varying ratios. Like the Legacy vs LGT. If you want to confirm a salvage car's gear ratio, you could take down the last 8 of the VIN and call your local Subaru parts department and ask them. Sometimes they may want the whole VIN, but if you're standing at the car when you call, easy peasy.
 
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