06 forester shaking under acceleration

[Mblattel]

My 2006 subaru forester L L Bean Edition has started shaking at around 55 about a year ago. We knew the axles and struts were bad, so we had them replaced a few months ago. Since then, the car has remained shaking at 55 so we had the alignment double checked. Shake remained. Got new tires all around. New driveshaft also. Now the shaking has gotten to the point where I'm afraid it's going to break down catastrophically. It's not a severe, teeth rattling shake, its pretty mild, but the fact that its persisted so long now has me nervous. It only shakes under throttle, turning does not change whether or not it will happen. It generally happens going uphill or while any moderate throttle is used. The shake stops as soon as you put it in neutral, and stops when you let off the throttle. Revving the car up while doing that speed while in neutral has no shake either. I'm almost fully convinced it needs a new transmission, but I cant afford to buy one and have the transmission not be the issue. The car has a 4ate transmission and has had the fuse in it disabling the rwd since we have owned it. Reason being that the car would shudder turning in reverse and sometimes in drive. I currently have the car on blocks, all wheels removed and put it in drive and watched the front axles spin at idle. I could see the cup of the axle against the transmission has a slightly elliptic rotation. Ive heard people mention that aftermarket axles aren't balanced well and to go OEM. I have a hard time believing that to be the cause of this, because this shaking was the reason we replaced the axles. My front diff doesnt have any filings in the oil that I could fish out with a magnet and doesnt appear to be burnt. There was a steady rhythm of clack clack sounds from the front axle *binded one at a time, rwd disengaged* and both axles exhibited the same issue. Open diff in the front, lsd in the back. Engaging the awd didnt change any symptom of the front, but did mimic it. Transmission doesn't slip at all, no late engagement after stopping. Wheel bearings have no play, tie rods are good, ball joints are semi-good, but that being bad shouldnt be causing that with the car sitting on the frame rails instead of the tires. When turning the awd on, I could hear the clutch pack making sounds like a loud hum, but again, no change in behavior by engaging the awd other than the rear end mimicked the front. With the awd off I can spin the driveshaft and rear wheels by hand and dont see any transfer to the front. I'm a new subaru owner and not regretting my decision to buy one, just totally engineered different than anything I've ever had before. Any ideas? And methods to 100% confirm an idea? Quick recap, new front axles, new shocks all around, new driveshaft, new tires, alignment, rebalance tires and rechecked alignment. Axle has elliptical rotation, out of round by perhaps 1/16th inch at end by transmission

 

Here is a link to a video on YouTube so you can see what I'm seeing. 

Passenger side

 Drivers side 

 

Edited April 30, 2020 by Mblattel
Link to video of issue

[1 Lucky Texan]

are all 4 tires identical? Subaru's awd system begins being 'unhappy' with as little as 1/4" difference in tire CIRCUMFERENCE. Same size/brand/model and near eact other in wear is a requirement. Could be why the FWD fuse was installed? Also, if incorrect matching of parts with either a trans or rear diff swap occurred, you will also get torque bind.

aftermarket axles are a continuing nightmare of poor risks. Best 'value' approach if axles are suspect is to get used OEM and reboot them, at least consdier rebooting the inner joints.

check that the inner joints are properly pinned  (roll/spring pins hold them on) to the stub shafts in the trans - as well as the stubs properly seated in the trans.(there are circlips that retain them)

does the vibration continue if you swap tire pairs front to rear?

is a brake caliper stuck?

[heartless]

Yes, that axle being "out of round" as you put it can indeed be the cause of your issue. Aftermarket axles are a known problem in these cars, often right out of the box.

another thing to look at would be tranny mount - make sure it is not torn/broken from all the vibrations.

[idosubaru]

Axles. make absolutely sure they’re fully seated into the trans. 

Aftermarket axles are garbage. I don’t know how many bad and failed aftermarket axles I’ve seen.lost count years ago. It’s nearly routine if you’re around even a small volume of Subaru axles. I’ve written a lot about them if you want to search here under my username. Or search “aftermarket axles garbage” or “trash” and you should begin to step into the light  

Buy two front Used OEM axles and reboot them.  I’d offer to ship you two but they’re so cheap it’s not worth it.  Yards have them for $15-$35 each. Other than being lazy, which I do understand, but there’s no reason not to use OEM axles in this situation. 

of course you’ll want to verify but it would be ZERO surprise for this to be the axle. Oh but you replaced it already - Yawn - still no surprise.  4 in a row would probably be surprising.  Two - not even close  

Consider yourself lucky they haven’t just blown apart while driving - I’ve seen that multiple times two on brand new axles. That doesn’t even surprise me now. Trash.  

There’s a couple other things it could be but you haven’t described any other symptoms that point to them, they’re less common and more expensive so rule out the axles first...and you’ll be done. 
 

Edited April 30, 2020 by idosubaru

[forester2002s]

I agree that axles are probably the main problem.

But you should check the 3 engine mounts:

- 2 lower-mounts between the engine and cross-member;

- 1 upper-mount (dog-bone) between engine and fire-wall.

If any of these mounts have failed (delaminated rubber?), this could be either the cause of the vibration, or else collateral damage from another source (e.g. axles).

[NV Zeno]

I agree with Idosubaru above.  Same thing happened to me some years back.  Shaking stopped whenever I let off the gas.  The problem developed really fast for me.  Cheap axles of course, started shaking a little bit on my way to work, a 25 mile commute.  WAY worse on my way back home that day, barely driveable by the time I got home.

[Mblattel]

Alright guys. Appreciate the insight. Sorry, I lost the link back to this page so I just now got around to seeing your responses. We went ahead and got the axles swapped out under warranty just because we had to go get other parts as well, but will definitely look into rebuilding an OEM set. Tires are 100% not the issue, I've had them all replaced since this issue had started in September. It's just gradually getting worse. Also, drained the front diff and changed fluid today, had a minor amount of metal on the magnet. Inspected the gear you can see through the drain hole, no obvious damage to that particular gear, but if you were super critical there were some minor irregularities, but no sticky spots. Is it normal for the splines the axles slide into to have play side to side? If I stick my fingers in both sides and press the gears towards each other, it definitely causes some binding to occur. Waiting in my seals to come in before i can do anything else right now. And also, immediately after the axle seal, there is what looks like a bearing. I cant get either side to turn. Is that actually just a guide or is it a bearing? I looked at the exploded diagram from subaru and they say there is a bearing there but when I look at the bearing itself on their page, it doesnt look exactly the same. I'm seeing like an extra sleeve through the bearing or something. So my question is does that bearing just have the axle go through the middle, or is there some sort of sleeve that's holding that bearing. Idk how to say what I'm trying to ask. Lol. I'm poor as codswallop and am trying to get back on my feet and this is my work vehicle. I'm just concerned about that bearing and the gears being able to be moved sideways. They dont wiggle at aa angle, just slide straight. I'll put a picture of the bearing thing im seeing tomorrow if needed. Thanks for the help guys, I just cant afford to replace the axles and find out the trans is fkd. I'm barely in a position to buy anything at this point 

[idosubaru]

There are only two things that cause your symptoms...assuming I’m reading and picturing them right:
1. axles - specifically the front inner joints.

2. front diff - always...(or usually?)....accompanied by noise. 

you don’t have any noise so front diff seems unlikely.  When the bearing or R&P have any play it’s hard for them not to make noise...particularly if they’re getting worse, but I guess it’s possible.  

the minor metal on the drain plug is hard to assess without seeing it and knowing how long since the last front diff oil change.  But typically some debris is normal assuming it’s not changed frequently which is often the case. 

[Mblattel]

Ok. So, I have access to the tool the junk yards use in my area to find and share parts with each other, and they're wanting $65 for each axle. Would you be willing to ship me 2 of them if I paid you through paypal? I think we are going to try these axles first however, like I said, definitely trying to make this as cheap as possible. Our axle seals were bad, so I'm hoping that could perhaps be the culprit. And as far as there being sound, theres a slight clack clack sound when I put the car in the air and in gear, no wheels on. While driving you couldnt hear a clacking noise, but there was a loud sound similar to a truck with mud tires driving on pavement. 

[Mblattel]

Yellow arrow points to what I am asking is supposed to turn or not. I expect it to be stationary and believe the red arrow to be pointing at a bearing. But is the yellow arrow supposed to move or not?

[CNY_Dave]

Yellow and red parts would turn together.