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2001 subaru forester drive shaft or viscous coupler? Help!

This is the third time the dealership has removed and replaced the drive shaft in my 2001 subaru forester (manual transmission - 150K miles); I still have the same symptoms.

Somewhat over year ago, my car developed a notable clunking (that felt like someone with hard-toed boots was kicking the underside of the car right in the middle) whenever I started out in first gear, and especially obvious when starting out under torque conditions, such as at a slight incline or turning.

The dealer (this has been a dealer-maintained vehicle) diagnosed a failed drive shaft, which was pulled, rebuilt and replaced. The symptoms continued and the process was repeated (no charge to me the second time). Still, the symptoms remained. They seemed baffled and tightened someing - a bearing (?) which didn’t seem to help. They wanted to wait until another 2001 forester showed up on their lot to compare it with mine - but this never came to be. Finally, the car developed a servere wobble (when starting out, and especially when turning), and then a scary wobble / vibration at higher speeds (40-60 mph). I took it back, wondering if perhaps it had been misdiagnosed to begin with. They tightend something and sent me on my way. But the wobble and vibration (and clunking) remained. Again, they pulled the drive shaft and replaced it with a new driveshaft. They explained it a failure of something to do with the U-joint.

The severity of the wobble is greatly diminished, but still there. The clunking is definitely still there (starting out in first gear, and accentuated by incline or turning), and the higher speed vibration seems to be abated at the moment.

Another subaru mechanic drove it with the severe wobble and, vibration and clunking and diagnosed it as a failure of the viscous coupler (about $1400 to repair). But since the drive shaft was still under warrenty, they suggested going back to the dealership.

The dealer has replaced drive shaft three times! I am wondering if the dealership misdiagnosed the problem to begin with. Or if the drive shaft problem caused or contributed to the failure of the viscous coupler (if that’s what it is), or if these were two separate, but co-occurring problems.

The dealership is obviously tired of dealing me - but they never have fixed the original problem, it seems.

I’m not an aggressive driver and try to take really good care of the car - maintenance, etc.

Any ideas?

Thank you thank you thank thank you thank you

Time to read up on the lemon law for your state.



“Time to read up on the lemon law for your state.”

Joseph–Re-read the OP’s message. The vehicle is now at least 7 years old!

Lemon Law? I don’t think so.

Read the fine-print on your extended maintenance contract. You may be able to get the “Home Office” involved (constructively).
A suspension and alignment shop may be able to diagnose the problem. Check your contract to see if they can repair the car, under the contract.

Thanks for the posts - What extended maintenance contract? Yes, the car was purchased seven years ago. It has had drive train issues from the beginning - from a pressure plate that made of defective materials (and beyond warrenty), to a big bad rear differential problem and now this. Any thoughts about the vicous coupler diagnosis? Thank you - sue

The viscous coupler could produce most of the symptoms that you describe, but I am not sure that it would produce a clunking noise. That is the one part that has me stumped, but I do think that the diagnosis of a bad viscous coupler certainly has some merit.

I would suggest that you pre-arrange with your mechanic that, if the installation of a new coupler doesn’t fix the problem, he would remove it and put the old one back in–and only charge you for labor.

Thank you - Although, I asuume the labor is majority of the cost of the viscous couple. Thanks for confirming the symptoms related to that. The thunking seems to be play in the drive shaft knocking against the frame of the vehicle - or that’s what I’ve been told.

Sounds like they’re referring to a center carrier bearing on the driveshaft. At 150k miles it’s entirely possible this is the problem.
A quick look at several parts sites do not show this carrier bearing, or U-joints as being available. This could mean either going to the dealer or an independent driveline shop. The latter is preferred because it will be much cheaper for them to repair it rather than replace the entire unit.
If you live near a major metro area look in the Yellow Pages under “drivelines”.

Regarding the bit about a bad pressure plate due to defective materials, I would take that with a large grain of salt.

Thank you for the recommendation. There is a dedicated subaru shop (not the dealer) in town. If there is an entirely new drive shaft installed now, wouldn’t that mean that there is a new carrier bearing (it’s part of the drive shaft?)? Right now the dealer is telling me that I have 6 months warranty on this drive shaft.

The word “rebuilt” can mean many things on a driveshaft. To me, it means all U-joints and the center carrier bearing was replaced. Some may consider the replacement of 1 U-joint a “rebuild” job. I had forgotten some things in your original post and they raise a red flag over what has allegedly been done and what you have been told.

First point is the drive shaft being rebuilt and allegedly replaced THREE times? Anyone who would do this is doing nothing more than wild guessing; and guessing very badly.

The second point involves a question. They claimed to have replaced this driveshaft 3 times. So who in the world is paying for all of these allegedly defective driveshafts?
I hope you’re not going to tell me that the dealer claims these genuine Subaru driveshafts are defective and the parent company (distributor) Subaru of America is covering this under a parts warranty.

I assume the shaft that has been redone 3 times is the one going from viscous coupler to the rear differential? Seems that if they ran the thing while it was on the lift, that they would be able to see the shaft wobble, or whatever wobble.

Have they ruled out wheel bearings, poor struts (which can result in wheel hop when taking off), and the front top strut bearings?

The rebuilt drive shaft is not from a subaru manufacturer - it is from a supplier that rebuilds these in a neighboring city (northern colorado). On visits between the actual replacement of the drive shaft they have tightened / adjusted the carrier bearing, with poor results. I’ve driven the car for one week since the last replacement and, although the wobble that occurs when I am turning seems to be gone (for now), the clunking when taking off in first gear from a complete stop is still present (which was the original sympton). I was told that the warranty was from the shop that did the rebuild. When I asked about a warranty on this round - the subaru dealer shop supervisor seemed somewhat arbitrary in saying “6 months.” And to respond to the question below - yes, the it the driveshaft that goes from the viscous coupler to the rear differential. No one has mentioned wheel bearings, poor struts, etc.

Thank you, folks, for your input and thoughts on this. I think I will call the dealer and ask them if the center / carrier bearing was replaced in the rebuild. Then, from now on I’ll take it into the other independent subaru specialists in town.

Thank you for clearing that up. If an authorized Subaru dealer was changing the part out that much they would be way up the creek without a paddle because SOA is not going to pay repeated warranty claims for the same part.

Let me ask another question. Did this clunking noise happen to start after a clutch replacement? I’m wondering if someone may have left the pitching stopper loose, or off depending on how they performed the clutch job.
This is what it looks like.

This is not the exact one for your car but gives you an idea of what the part looks like.
The pitching stopper is a top mount that prevents the engine from torquing up and back. If left loose, off, out of adjustment, etc. in some way then that could very well cause a clunk when taking off.

Normally the pitching stoppers are removed when doing a clutch job. This allows the engine/transaxle to tilt backwards a little more and makes the removal and installation of the transaxle much easier.

In answer to your question about when the clunking began - no, it was quite a while (years) after the clutch replacement (which they did twice in short succession - due to “defective materials in the pressure plate” - the car’s clutch stuttered from the get go).

If I have my elbow on the center console while driving, I can feel the clunking right under there. It is a rapid kicking feeling - like someone kicking the underside or frame with boots on - only very fast. Maybe 3 to 5 “kicks” at initial start up under torque conditions in first gear (slight incline or turning).

I can still feel the wobble, to a much lesser degree than before the last drive shaft replacement, when I am doing a hard turn (e.g., 90 degrees) at a slow speed like turning into a parking place.

thanks, again, for taking the time to think about this!

It’s not likely you had crummy pressure plates. A stuttering clutch is caused by an oily flywheel (leaking seal), burnt flywheel, worn pilot bearing, worn transaxle mainshaft bearings (unlikely), worn crankshaft thrust bearing (unlikely), etc. Someone probably covered their tracks on a subsequent visit.

Some possibilities here could be a bad rear transaxle mount, faulty front halfshafts, or a pitching stopper problem.
An example here regarding the halfshaft problem. Most shafts will click or knock when worn but it is entirely possible for a shaft to have an odd wear pattern which leads to the shaft binding while in certain positions. This can cause the car to wobble, lurch, or cause the transaxle to thump.

Last year both shafts were replaced in my daughter’s car (rebuilt units). About 2 weeks later she called me from the side of the road and was afraid to drive the car any further because it was wobbling and lurching so bad. So Dad went and drove the car home at slow speed and with both hands on the wheel. It wa BAD in caps.
Disassembly showed that one shaft was seriously defective and this was the source of the problems. Replaced it and the problem was cured for several months until the other rebuilt shaft went bad. To finish the story, the parts house ordered 3 or 4 more shafts until I got one good one. Some of the “new, rebuilt” shafts were total junk right out of the box.

I would examine the rear transaxle mount, the pitching stopper, and both front halfshafts. The shafts may be impossible to check without removing them but once on the table, assuming someone knows what they’re doing, should be able to easily pinpoint any problem in that area. Hope some of this helps anyway.

OK4450, I take it that those rebuilt shafts didn’t come from Subaru. Is that correct?

Yes, Cougar, those rebuilt shafts did not come from Subaru. - oops, you were asking OK4450 about his drive shafts, not me.
And, thank you, OK4450 for your thorough responses. When I find out what’s going on, I’ll post it.
I appreciate all the input, even though it’s a little intimidating to a car ignoramous like me.

Just an update to satisfy any curiosity… After talking to the service manager at the subaru dealership, once again, I brought my car in and drove with the service manager to demonstrate the clunking. They had another 2001 forester in for an engine rebuild, so they swtiched out the drive shaft on that vehicle to mine and we took another test drive. It drove quite differently - no clunking, no whining (another noise that occurs when slowing down), and no vibration. So - they are going to talk to the shop that did the rebuild on the drive shaft and ask what they can do, since they seem to have isolated the problem to the drive shaft. Of course, they returned the good drive shaft to its rightful vehicle, and the funky one (apparently) to mine while they negotiate with the rebuild shop.