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2008 OBXT; 2007 Spec.B; 2003 WRX
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Discussion Starter #1 (Edited)
Hi All,

I recently finished installing my 2" lift - HotBits DT1 coilovers with ADF 2" multi-link spacer kit and new OEM top hats, and I'm getting some driveline vibration (2008 XT, manual). The vibration occurs at ~35-45 MPH, in any gear. It is much more pronounced if I'm accelerating through that speed range. If I'm cruising at 40 MPH it has a kind of rhythmic amplification or harmonic oscillation (whummm whummm whummm type of sound, about a second apart from each other). There to be some similar vibration right around 60 MPH as well, but much less intense than the lower speed, barely noticeable. I thought driveline at first and fabbed up a couple of carrier bearing spacers, but that didn't fix it. I think it helped, but certainly didn't eliminate the root cause(s).

My understanding is that inner CV joints can exhibit this behavior, particularly after a lift. I've gone under the car and checked for play - There is some in both inner joints, 1/8" or so.

I've also checked the driveshaft for play, at the front u-joint and carrier bearing. There's a small amount of lateral play in front of the u-joint, not in the joint itself - output shaft bearing? There is also some play at the carrier bearing, but it just feels like the rubber is flexing, doesn't feel like anything is actually "loose." I'll check the rear u-joint in the AM.

A few specific questions:

1. How much play, if any, should CV joints have?

2. How much play, if any, should there be at the output shaft bearing?

3. How much play, if any, should there be in the carrier bearing assembly? Should I be able to move it with light/medium effort (pushing/pulling from under car with one hand)?

4. How much play, if any, should there be at u-joints? As mentioned I don't feel any there, and I don't think there should be, but I'd like to confirm.

I think the only other things to consider are engine mounts, pitch stop, trans mount. - How does one verify that those are ok?

Anything else I should be considering?

Many thanks in advance for any advice!

Here's a pic of the offending battlewagon :)

501708
 

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Premium Member
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6,831 Posts
@traildogck makes transmission mount inserts that often help with raised Subaru driveline vibrations.


 

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2001 VDC/SC One of a Kind
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14,755 Posts
Another vibration issue is the alignment. If it wasn't set proper the wheels fight each other and cause vibration. Standard, lifted, or lowered makes no difference.

With the angle change on the shafts, having any play in the joint can cause vibrations.

The center carrier can have some movement. If the bushing is torn or ripped then it should be replaced.

There will be a minimal amount of movement from.the output shaft. And I do mean minimal. It may be worthwhile to take the rear cover off and check the bearing and race for wear if you feel movement.
 

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Registered
2008 OBXT; 2007 Spec.B; 2003 WRX
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89 Posts
Discussion Starter #4
@SilverOnyx Thank you, I am aware of those transmission insert mounts. I'll give them a closer look after inspecting mine. From what I've gathered from his eBay page, he doesn't make them for 5MT or Gen.3 Outbacks? Or maybe they're the same as one of the several he does have available.

I'm leaning toward it not being a trans or engine mount, due to the rhythmic nature of the vibration. That leads me to think it's a rotating part. This is more of an intuitive guess than anything though. Not ruling it out yet.

@cardoc Excellent info, thank you. Forgot to mention alignment - it has been aligned post-lift. The shop did a great job. Also, wheels and tires are the same as before the lift, and in the same locations, so I feel confident ruling out anything associated with those.

I'll try to get under the car again today to get more specific about how much play and where. My first suspicion at this point is inner CV joints, with output shaft bearing as a second.

Thanks again! I'll keep this thread updated with any new evidence :)
 

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2005 Outback 3.0R VDC/VTD/LSD 5eat , 2.8'' lift
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1,726 Posts
but if some people dont have any vibrations with lift means it must be something else like some parts there are used too much some bushings i mean. its not that hard to well change them all in front as there are not many there. something has play there thats why vibrations
but first make sure alignment is good, as front wheels will vibrate from any alignment off
CV joints can make vibration but i wouldnt believe it would be this kind, i mean i lifted it 7cm more then most people do and i dont have any vibrations after alignment.
wheel bearings are shot, but it should be felt before lift too , still check bearings.
frist check alignment. any play there on end links means it will be felt while driving
 

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2008 OBXT; 2007 Spec.B; 2003 WRX
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89 Posts
Discussion Starter #6
Well, this just happened...

501842


While I was under there looking at this mess, I gave the shaft a couple good tugs back and forth and could definitely feel side-to side play in the inner joint. Not much at all, but still...no bueno. Looks like new axle(s) are in order. I'm pretty sure that the standard re-grease and re-boot won't cure this vibration issue.

After a stupid amount of online reading, and eventually speaking with two trustworthy Subaru mechanics, I'm rollin' the dice on a pair of Cardone HD axles (66-7355HD). Bring out the torches and pitch forks. :) They'll be here next week.

Side note: I saw this Inner Joint Assembly at SubaruOnlineParts, but it looks like it's missing the trunnion and three associated bearings. It states SFJ as opposed to PTJ, but I think those are referring to the same thing (shudder-free joint vs pillow tripod joint). Anyone have experience with these kits? They have them for the outer joints too. Might be a useful kit for some scenarios, like the one I'm in, for example. I'm going to keep my OEM axles and might try one of these kits someday, but in the meantime I'm curious about them.

@scalman Alignment is spot on:

501843


If it turns out my bad vibes are not caused by the front axles, I'll be looking more closely at engine and trans mounts, and output shaft bearing. At a glance they seem OK, and the play at the output shaft is minimal. We shall see. I'll keep the the thread updated.

Happy Friday!
 
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