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Old 03-08-2014, 12:45 PM   #1
scoobydrewbydoo
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Default Center differential bearing replacement

Ok guys, If you have a high mileage 'Baru you probably have or have heard of the whine on acceleration, usually in 2-5 gear.

I also have a grinding on decel in gear, but that is another story.

I was tired of hearing the whine so I spent a night replacing the center diff bearings, and here's how I did it...

I referenced this thread for some inspiration
http://forums.nasioc.com/forums/show....php?t=1170285

Thanks to VideoGameWrx for that.

The repair manual has all of the usual, remove the negative battery cable, place vehicle on lift, etc., etc... you can do as much or little of this as you like, I did not unhook the battery cause I didn't want to lose my radio stations. Once on the lift I dropped the exhaust from the end of the downpipe back. A little PB Blaster helps a lot.

The cross member is in three pieces and the nuts and bolts are probably rusted, again, PB Blaster. But you really don't need to take it apart. Some would say that you need to support the end of the trans, but I found its not really necessary. Do it if you like, but the pitch mount will take care of it.

Release the back of the drive shaft and the center bearing support, then take out the prop shaft.

This is a perfect time to replace the lever shaft bushings at the back of the trans and the body. Ref here:

http://www.prothanesuspensionparts.c...FSXl7AodtH8AHA

Pry out the rear one while its still bolted and then the front. I had to cut the old front bushing out of its barrel, but they were pretty old. You may be able to push it out, but a hack saw works really well.



its pretty obvious why the shifters feel so squishy when you see the bushings.



Next unbolt the shifter shaft and then drive out the roll pin in the shifter "Joint". This is what Subaru calls the U-joint that connects the shifter pieces. One set of the bushings on it were wiped out and the other was fine, but it still made for a loose shifter

P/N for the "joint" is 35047AC030. I also got the roll pin, just in case, but found the new one really hard to install, so I just used the old one.





So now you have a great view of the back of the trans, and the 14mm bolts holding on the rear cover. Remove them, BUT, be ready with a catch pan or a friend cause as soon as you break the rear cover loose it will come off in a big way and the center diff ($500) will come tumbling out.







This what you have. If all you are doing is replacing the bearings, go no further, but I needed to replace my shift shaft seal too, so I continued.
Now take out the reverse switch and neutral switch, and all of the 14mm bolts holding the mid-case on. This is a fairly simple matter, but there are dowels holding it on too. PB Blaster and a few light taps with a punch on the end of the dowel will help. Then, very carefully tap on the housing with a dead blow or rubber hammer. A ball pein or other metallic hammer will distort or crack the case. You may want to use a large screw driver or pry bar, but BE CAREFUL. You can seriously damage the sealing surface of the case. If it feels like its taking a lot of force to remove it, stop! check everything again, make sure nothing is binding.

The mid case will come off with the shift shaft. This a great chance to look at the inside of your trans, check the shifter arms for wear, bending, cracks, gear chips, etc. Once you have it out, its a small matter to drive out the old shift shaft seal and drive in the new one. Remember, a little force applied in the right way works much better than a lot of force the wrong way. An appropriately sized socket works great for driving in the new seal. I always coat the new seal OUTER diameter with some blue thread locker. It lubricates as it goes in and seals it once its in there. Clean the surfaces with a razor blade or brass brush. Try to keep the particles off of the gears and out of the case. I just lay a rag over that stuff. Then re-install the midcase with some RTV. Lube the new shift shaft seal and re-install the shaft itself. Its kinda tricky to get the shaft into the selector shafts, but practice makes perfect. Tighten to bolts to about 45 Ft/lbs, but don't over do it, its just aluminum. now your back at the bearing section.

So this is what you should have by now...



This pic shows all the bearings off, but imagine they're still on. The main center diff support bearing is bolted to the back case, unbolt it, clean it and remove the circlip. The flange makes it easy to pull the old one off, its not on there really hard.



Some lube and a few well placed hammer blows will install the new one, or if you have access to a press, that's better. Re-install the circlip and bolt it back up. Thread locker is always a good idea. Again, don't over do the tightening.

the outer race that is also in the rear cover comes out easily, but watch the shims behind it, they are important. I just hooked something behind the race and it came out. The new one just slips in there, remember the shims. The new race is a different size because Subaru had a problem with them, so these are updated, don't fret. Here's the TSB# 03-70-12R
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Last edited by scoobydrewbydoo; 03-08-2014 at 01:46 PM. Reason: updating
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Old 03-08-2014, 01:39 PM   #2
scoobydrewbydoo
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Now, you have the rear output shaft and center diff left. There is a bearing at the other end of the output shaft that is in the midcase that also comes out pretty easily. Look out for shims here too. The inner races installed on the shaft are more difficult to remove, so if you have a press, now is the time to get to know it.



The little one on the left is easy, just support the outside of the cage and press the shaft off, make sure you catch it. If you don't have a press, a bench vise and hammer should work, but please find a piece of brass or aluminum to put against the shaft while you hammer so you don't deform the shaft. The other one is harder. If you have a good bearing separator, it would work fantastically. I didn't. I used a couple good chisels on a relatively soft surface (wood is best) and wedged them between the gear and the bearing race. It's slow going and you must destroy the cage to do it, but it works.







Now, its a time honored tradition to use old bearings to install new ones and this job was no different.

When I cut off the old cage from the small one (midcase end of the shaft) this is what I found



That was definitely the source of my noise. Again I turned to the press for help. Set the new bearing on the shaft supported by the old one and press. The small one was easy cause its at the end, the larger one you really need a press for. If you have to hammer it, do the large one first so your not hammering on your newly installed small bearing.

The last bearing is the one on the diff itself...



Evenly placed chisel blows will remove it forthrightly. Then use the old bearing and a bench vise to put the new one on. I like putting a CLEAN piece of wood on the diff in order to drive it into the bearing. By clean I mean a piece that you have washed thoroughly in a parts washer and then rinsed in water. No particles.
Now, clean all of the gasket material off and place the new one on. A little RTV here doesn't hurt either, but its not necessary. Install the new output shaft seal with some thread locker on the out side and gear oil on the inside, or di-electric grease. I like using di-electric grease because its non-reactive, doesn't slide off and is easy to clean.



Re-install all the other pieces and fill with gear oil. I used 80/90 conventional, but use whatever you like. Thick is good, but will cause more drag on the gears til it warms up. Synthetic is good, but more expensive. Just make sure its full and oily.
Now, enjoy noise free acceleration!

If you want, you can go to my googleplus picture page and see a video of the old diff support bearing. The new one made no noise at all. My google+ ID is harveyottotech. All of the pics from this job are here.

This shows the size difference between the old bearings and the updated ones.







Well, that's all folks, Thanks for reading, and good luck. Any questions, just ask here or shoot me a PM.

Harry
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Old 03-09-2014, 05:44 AM   #3
schwinn
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Great writeup... and just in time for me, as I believe I need to do this myself on my 06 Legacy GT. A few questions for you... you mention you got tired of the whine... have you had it for a while now? How long? Just curious to see what kind of timeline I'm looking at for my whining transmission.

You also show the "updated" bearings versus the original ones... did you select new replacement bearings, or are these what you get today for these part numbers from Subaru (ie, they updated them)?

Is there a good drawing part list you can point me to? I'd like to see what the assembly looks like and make sure I get the right parts... I can't seem to find a proper exploded view for this section.

Thanks!
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Old 03-09-2014, 11:30 AM   #4
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I bought the car in September of 2012 and I started driving about 4 months later. It had a whine ever since I had the car. It got worse but only after I auto crossed it a few times. As you can see, the small bearing was about to get much worse. I wouldn't put it off for very long cause all of the metal pieces are going into the fluid and into everything else. Its really hard to tell how long something will operate in a compromised way.

The bearings are already updated, that is the way you get them from Subaru when you order them. You don't have to specify.

The link at the top of my post show a thread from VideoGameWrx and he has an exploded view. Not the best, but a google image search should show some results. This is a good link though its not exactly what we are doing, it has a great diagram.

http://www.subaruforester.org/vbulle...ce-them-46979/

Thanks again.
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Old 03-16-2014, 09:29 AM   #5
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Excellent - thanks for the reply! I agree, I'm not a fan of letting it continue this way, but then again the sound isn't so bad on my car, so I think it's probably just the bearings are worn/unhappy... not to the point of bits/catastrophe just yet. I plan to dig into it when the weather warms up a bit (it's cold here in MA!)

Thanks for the detail on the new larger bearings.. and the link to some more info on what I need in there!
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Old 03-16-2014, 10:22 AM   #6
scoobydrewbydoo
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Your welcome. Just glad someone could benefit from my problems, also I love doing stuff like this

Andrew
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Old 04-21-2014, 03:18 PM   #7
Cvryan
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This is incredibly helpful to see with pics!

I'm hearing a constant (not just acceleration) speed dependent whine/groan that changes with wheel speed through all gears and neutral. It is higher pitched when pressure is put on the shifter in gear and going in and out of gears. Is this what you experienced, or am I hearing something different?

I recently determined (with help for NASIOC, of course) that my center differential/viscous coupler is locking up under turns and causing binding when hot. I've been driving it (approx. 2-3 months) while I save $ because I have done a lot of other expensive work recently (timing belt kit, Head gaskets, etc). Wondering if its center diff. bearing noise related to locking viscous coupler or coming from elsewhere in the transmission?

I plan to get it on a lift with stethoscope soon!
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Old 04-21-2014, 04:04 PM   #8
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Thanks, I appreciate it. My whine was only on accelleration and a crunching/ grinding on Decel in gear. The whine was caused by the bearings but not the grinding. If it makes noise in neutral too, I would suspect a wheel bearing or center support bearing on the drive shaft. It could also be caused by the rear
end. Mine wouldn't make the noise on the lift, had to be driving. I used a chassis ear to determine it's source. If you are going to replace the center diff, I would replace the bearings anyway, just cause your in there.
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Old 04-22-2014, 09:55 PM   #9
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Thanks for your feedback. Are all the suspect bearings located in the extension housing with the center diff assembly?

I was leaning towards inside the transmission because it changes pitch when I move the shifter.
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Old 04-22-2014, 11:00 PM   #10
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Yes, all 4 of the bearings are in the extension housing and are easily replaced. As long as your not replacing the shift shaft seal, it's super easy. It could be the center diff bearings that are causing all this noise or it might a couple different things. Get all the bearings when you get the diff, but remember, if it doesn't go easy, stop and look again.
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Old 06-17-2014, 05:19 PM   #11
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nice write up. my bugeye is up on stands in the garage waiting for some xfer case bearing swap love.
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Old 06-17-2014, 11:20 PM   #12
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Excellent write up. I have all the new bearings and seals for this replacement project, just have to get it up on the lift.
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Old 06-20-2014, 02:27 PM   #13
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I did the same bearing replacement too because deceleration noise sounded extremely horrible with grinding noises. It was a pita. Because I had jack stands and no lift.
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Old 07-12-2014, 12:31 AM   #14
dead_eye
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FINALLY got to replace the bearings. Do you guys think this one was bad?




While we were in there we also replaced the driveshaft bushing and oil seal. This turned out to be a pain in the ass. We pressed old one out and new one in without any problems, but when we went to put the driveshaft back in it did not fit! We ended up jerking the thing off with a cylinder hone for an hour.

The shifter roll pin is a pain to get out, unless you have a proper tool: http://www.amazon.com/Subaru-Axle-Pin-Removal-Tool/dp/B002YKK2HU It's really just a giant roll pin punch BUT it becomes a 30 second removal, and the pin doesn't get destroyed.
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Old 03-03-2016, 09:11 AM   #15
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Awesome writeup, referenced it for this job this past weekend and so far no issues, noise is gone. Just to clarify a couple of extra things that I figured out:

1. The shifter joint roll pin is actually in two pieces, an inner one and an outer one. Due to it being gummed up I didn't realize this at first and spent a while trying to figure out why the joint wouldn't slide off after removing the little pin. Eventually I realized the outer one was still in there, and after punching it out the thing slid right off.

2. For the two little roller bearings, Subaru did indeed change their sizes and includes new races with both of them. The old races, one in the rear cover and one in the case, at first looked intimidating to get out but I was pleasantly surprised to learn that they do come right out pretty easily.

3. I found this set of bearing separating/ pulling tools for something like $45 at Harbor Freight and they ended up being incredibly useful on this job:

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Old 03-03-2016, 12:49 PM   #16
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I just want to add to this for you all you can use the inner race to install the new bearings. This way they're evenly installed.
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Old 02-01-2018, 11:52 PM   #17
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I replaced my center diff and bearings today and this thread really helped me out. Thought I would add a few pics showing the bearing tool shown in post #15 in action pulling and pressing the roller bearings. It also worked great pressing the ball bearing on but I didn't get a pic of that.



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Old 03-07-2019, 01:04 PM   #18
Jack13
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Hi there ,
Thank you for your extremely detailed post, really helpful .
I’ve been dealing with similar noises and whines, but for me it started as wheel hops and very tight, right and left turns and would immediately go away as I went into second and straightened out and I would have no other issues at all ..no it’s does the wheel hop (feels like back wheels are dragging) and whines louder as I drive for longer (it gets hotter, I’m assuming that’s why )
Do you think this is also just bushings or does it sound more like the center diff ?
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Old 12-11-2021, 02:35 PM   #19
my name is joe
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How did you guys remove the race that's still left inside the transmission? The smaller one. The rollers with the bearing is on the shaft but what about the other end? The race on the housing is easy to knock out since you can get behind it but the one left on the trans itself is a bit difficult to get behind without taking the trans out. Replaced everything except that one. Having some difficulty removing it.
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Old 12-14-2021, 08:49 PM   #20
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Quote:
Originally Posted by my name is joe View Post
How did you guys remove the race that's still left inside the transmission? The smaller one. The rollers with the bearing is on the shaft but what about the other end? The race on the housing is easy to knock out since you can get behind it but the one left on the trans itself is a bit difficult to get behind without taking the trans out. Replaced everything except that one. Having some difficulty removing it.
I'm about to attempt this myself but from my research (which is Youtube videos ) you can use a narrow pick to get that race in the trans out. It should slide right out.
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Old 12-15-2021, 12:24 AM   #21
my name is joe
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Quote:
Originally Posted by subezero View Post
I'm about to attempt this myself but from my research (which is Youtube videos ) you can use a narrow pick to get that race in the trans out. It should slide right out.
Mine actually didn't glide out as easily. Tried multiple picks. It eventually it came out with some convincing. I also went to a transmission shop to have them replace the harder to swap the bearings. I over paid them but it still came out to less than buying the bearing removal tool from harbor freight. I figured I wouldn't really ever use that tool again and decided not to and they pressed it in for me really easily.

Last edited by my name is joe; 12-15-2021 at 12:49 AM.
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Old 12-15-2021, 12:52 PM   #22
subezero
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Quote:
Originally Posted by my name is joe View Post
Mine actually didn't glide out as easily. Tried multiple picks. It eventually it came out with some convincing. I also went to a transmission shop to have them replace the harder to swap the bearings. I over paid them but it still came out to less than buying the bearing removal tool from harbor freight. I figured I wouldn't really ever use that tool again and decided not to and they pressed it in for me really easily.
That's what I'm thinking of doing, just pulling the shafts and taking them to a shop to get the bearings replaced. Can I ask what you paid or how many hours they billed you for?
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Old 12-15-2021, 01:24 PM   #23
my name is joe
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Quote:
Originally Posted by subezero View Post
That's what I'm thinking of doing, just pulling the shafts and taking them to a shop to get the bearings replaced. Can I ask what you paid or how many hours they billed you for?
I bought two people lunch with drinks. It took them less than 10 minutes to replace the bearings.
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