Clunk- wheel bearings? Transfer case?

[aabbas]

Long time lurker here. My '98 Legacy Outback (manual 5sp 120k mi) has a clunk. It's a loud knocking clunk that happens sort-of randomly and singularly (i.e never any rhythmic repetition) when I'm accelerating, turning, or going over bumps. It sounds like it's coming from somewhere around the engine or center of the car, I'm not sure.

 

I had a jet-engine sounding noise about two months ago, and it turned out to be a bad front wheel bearing. I had both front bearings replaced at the dealer (I know I know), and right afterwards this clunking noise started happening and gradually getting louder and more frequent ever since. I let the dealer look at it again because I thought it might be something wrong with the job they did before, but they said it wasn't, and that maybe it stemmed from the non-subaru brake pads I had installed... something about the housing being the wrong size. And would I like them to put on Subaru-brand brakes. I passed.

 

So I took it to my local shop and they put it up on the lift with a guy in it running it and shifting. They listened from underneath and said that it sounded like it came from the transfer case. But they don't do transmissions, so I have to go elsewhere.

 

I'm wondering:

 

1) Do you think the shop is right?

2) Could the dealer have been right?

3) Does "transfer case" mean it's the VCD failing (I've heard this is common).

4) Would this (or some other explanation) maybe be related to the wheel bearing problem?

5) Could it be an engine mount problem?

6) Any other wisdom?

 

Many many thanks,

Alex

[mattocs]

I had a 'clunk' in my outback. It happend when I turned...went over bumps...slowed down...etc.

 

It was a rear strut that went bad. Whenever the car shifted it would make nosie. You might want to look into that...just rock the car at each corner and listen for any nosie.

 

 

PS. I missed the part of you taking it to a shop...haha...so it probably is not a strut.

[bulwnkl]

Since there isn't a transfer case, I don't think it's that. Our '99 Outback had something very similar. A 'clunk' or almost a 'thump' at not-reliably-reproducible times. However, it became semi-reliable at doing it around a corner with a little bump in it. It sounded to me like something forward of the cab. In particular, I thought suspension or crossmembers.

 

The dealer we bought it (used) from has a 'warranty' on all their used cars so we let them look at it. They said they didn't find anything but put a wrench on a bunch of stuff anyway to make sure all was tight. That more or less eliminated the problem, but we thought the car pulled slightly to one side. Took it to an alignment shop, that fixed the pull, but the thump/clunk was back. Took it back to the dealer who this time said they found something loose and tightened it. The service writer did not appear to me to know precisely what was loose, or else they really didn't want me to know what it was. That fixed it and we didn't have any more trouble with the car, but we only kept it about another 5-10,000 miles.

 

SOooo, I'd look to front suspension, frame crossmembers, or similar things. Put a wrench on every nut or bolt there is and see what you find.

[outback_97]

My 97 for a long time has had a noticeable clunk that is surface dependent, ie when one goes over uneven surfaces, washboards, driveway entrances that aren't smooth, etc. It's heard and felt in the steering column. Feels like someone is hitting the steering column with a hammer. It can be a singular percussion or rapid series depending on the surface.

 

There's a long thread on Nasioc that addresses this:

http://forums.nasioc.com/forums/showthread.php?t=368718&highlight=legacy+clunk

 

Is this similar to what you're experiencing? There's a TSB (Technical Service Bulletin) from Subaru (mentioned in the above thread), but I wasn't able to find many people that had had it done.

 

I went through a few trips to the dealer (before I found this TSB) but of course they found nothing wrong and either weren't aware of or didn't want to acknowledge the TSB.

 

Steve

[aabbas]

...It's heard and felt in the steering column... Is this similar to what you're experiencing?...

 

Steve

 

Thanks, great link, but unfortunately I don't think I have this steering column clunk. I can sometimes feel my clunk in the shift lever but never in the steering wheel.

 

So, let me get this straight, I don't have a transfer case on my car? I admit, I've never looked at my car's underside, but I thought that was what split power to the front and rear.

[bulwnkl]

So, let me get this straight, I don't have a transfer case on my car? I admit, I've never looked at my car's underside, but I thought that was what split power to the front and rear.

 

No, a transfer case is something you'll see on a pickup(or many SUVs, etc.). It is a separate housing/unit bolted to the back of the transmission. The driveshaft for the rear axle comes straight through it, and going forward from the "side" of it is the driveshaft that goes to the front axle. A Subaru houses all the mechanism that accomplishes the same task within the transmission. It also works in an entirely different way compared with a transfer case. A Subaru 5-speed actually has a differential in the "center" of the drivetrain. A 'classic' pickup-type transfer case has no differential-type mechanism in it. It is a simple dirveshaft straight through to the rear and then a chain or gearset driving the shaft that goes forward. Some of them you can engage or disengage the drive to the front axle, others you can't.

 

If you had an automatic tranny in your Outback, then you would have a mechanism that could possibly be called a transfer case, but not in the sense of the pickup-style mechanism described above at all. To me it would be too big a stretch to call the Subaru AT mechanism a transfer case.

HTH

[idosubaru]

will this clunk happen at contant speed or under accleration or braking?? or literally any time?

 

transmission, engine and rear diff mounts can cause clunks, though i would expect them to be fairly consistent. these should cause more noise when acclerating and not when holding a constant speed so you should be able to rule them out (or in).

 

if the pads are causing it, it's not because they aren't subaru pads. you could try swapping pads or having somewhere check to make sure they fit correctly and have the proper hardware (clips and such) on them to prevent them from moving inside the calipers. in this case there is no worry of failure or cause for alarm though so no need to sweat your brake system. if anyone gets near the brakes while yo'ure looking into this they could try tightening up the caliper mounting bolts, greasing the caliper slide and replacing the pads (they are cheap, though paying someone to do it is not).

 

you could have your ujoints inspected if you're not getting anywhere on this. the proper way to check a ujoint is to remove the entire driveshaft to see how tight or lumpy the ujoints are. driveshafts typically come off by removing about 6 bolts so it's very easy to do. you should experience vibration with a bad ujoint so this doesn't sound like a good option, but it's something to check.

 

a bad strut as well like mentioned earlier.

[aabbas]

will this clunk happen at contant speed or under accleration or braking?? or literally any time?

 

transmission, engine and rear diff mounts can cause clunks, though i would expect them to be fairly consistent. these should cause more noise when acclerating and not when holding a constant speed so you should be able to rule them out (or in).

 

Thanks for explaining the transfer case thing, and thanks for the pointers on what to troubleshoot. The noise never happens when I'm going straight at constant speed, it requires a turn or shift or gas or brake or speedbump.