I just purchased my fourth Gen 4 OB, a 2010 2.5i w/6MT, and knew it had issues problems for resolution. Needs a clutch (yeah, @97k miles), needed a timing belt kit (done - Aisin TKF-006 installed), and I also knew that there was an issue with the steering wheel and front wheels popping heavily when steering on sharp turns which I figured was due to bad outer CV joints on the front axles. No biggie, checked out Subaru for OEM axles...nah, gold plate without warranty at a pretty ridiculous price (I was doing both at the same time), so I purchased NAPA axles with a limited lifetime warranty. Got under the car to install 'em and...I found that very new Cardonne CV axles were already installed - good boots, no grease ejection, seemed fine. It appeared that the previous owner had replaced the OEM axles just prior to selling the car. Installed the NAPA units and the popping on sharp turns was still there after driving it for several miles. During my troubleshooting I noticed that there was no popping on sharp turns at all when first starting and driving the car after sitting all night - everything smooth as silk. After driving 5 or so miles, the popping on sharp turns returned - seemed to indicate something happened after the moving parts heated up. I'm now thinking that one or both front wheel bearings are shot - the grease heats up in the rollers and allows excessive side clearance and roller skip/stall during the heavier side load on the bearing during a sharp turn. This'll be my next project but I was wondering if anyone else has encountered this?
TheGreyHearse
Popping noise on sharp turns - Not CV axle issue.
Thanks, my friend. This was my first thought after replacing the CV axles - the symptoms that I was experiencing with sharp turn popping sent me that direction because of a CV axle outer joint failure on a VW that I owned many years ago (I cheated on that one...even though everything was heat-blued, I just packed it with grease, put a new boot on, and drove it another 100k miles. LOL!). Once I'd replaced the axles and had the same popping issue when warmed up this time I suspected the center differential but talked myself out of it ($$$'s and a PITA). I'd heard of wheel bearings causing issues during sharp turns due to side loading of failing bearings (and I've experienced it with other makes of vehicle) and looked that direction - when I had the axles out I noticed that the hubs seemed to be a little stiff when rotated. But the absence of an issue when the car is cold and the appearance of an issue after driving and warming the drivetrain up makes me look the direction you steered me - torque bind from a failed/failing viscous center diff. I'll do the test for this as spelled out in an article in the forum search you suggested and verify yea or nay on this. Again, thanks. I'll probably be on my back again pulling that transfer case extension (a few dollars lighter).
In my case I'm fairly sure that the center differential is the issue. The radial bearing (basically a ball bearing ring around the nose of the center diff) is causing some vibration when under load and the clunking likewise occurs after the driveline warms up - the silicone-based fluid in the center differential clutch has probably been overheated. Somewhere on this site there is a troubleshooting section/post for the center diff that involves lifting one side of the car with the front and rear wheel off the ground on the same side and checking if the rear wheel rotates when rotating the front wheel by hand, a procedure done first with a cold driveline followed by a test with a warmed up driveline. I'll check that post again when I find it but I believe that the rear wheel should not move when rotating the front wheel whether hot or cold - rotation hot indicates overheat damage to the silicone-based fluid making it sticky when it shouldn't be. At any rate, I'll be pulling the center diff for the vibration of the bearing mentioned above and I'll probably replace the center diff as well. From everything I've researched and read, the job isn't that difficult nor super expensive (around $450 for the diff which includes the bearing mentioned). I would imagine that the local dealership would charge a lot more - mine has a $100/hr labor charge and the work is likely 4 hours or so.
Yes, I know this is an old thread but an update should be made to it. As Seagrass said above, my issue was indeed torque bind. I replaced my center differential about three months ago and the problem is solved. Stivers Subaru had a great price for a new OEM center diff ($393; my local dealership in Fairborn, Ohio wanted $643) and the work took about 5 hours total with a few breaks for this old man. No drama, replaced the output shaft seal while I was at it. Thanks to all who commented. Now I'm going to rebuild that old center diff - there was a thread on an Australian Subaru Owner's site that discussed this. Gotta get some dimethyl siloxane of the correct centistokes, a couple of grub screws to replace the little BB-sized fill holes, and get it done.
If I'm not mistaken, an H6 engine has an automatic transmission (5EAT). I'm not familiar with the center differential system in a 5EAT (my car is a 6MT manual). The center differential could be your issue.
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