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Diff whine - solved

Old 25 November 2018, 10:57 PM
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ambassador1
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Default Diff whine - solved

Hi,

I've been lurking on the forum for sometime now, there's already so much valuable information here but I thought this thread might be useful to someone out there.

After a long search I bought a 2003 blob eye wagon earlier this year, as it had a tasty list of upgrades including STi turbo/intercooler etc...albeit with a 5 spd box. A few months in to ownership I developed a whine....my initial reaction was that it was something to do with radio interference, those of you who have run aftermarket sound systems may know the weird alternator type whine you get from faulty RCA cables. After a few tests, it was clear it wasn't anything to do with the stereo, the whine sounded like it was coming beneath the gearstick area.

My next thought was it was a bad front passenger side driveshaft, as the boot had split and shed some grease. I replaced this, but the whine remained. Next step, I got the car up on ramp and used a stethoscope which confirmed the whine was coming from the rear of the gearbox in the diff housing.

Doing some research, this thread was VERY useful: https://www.scoobynet.com/drivetrain...-2006-wrx.html

So, having sat on my hands most the year I started planning the job and sourcing parts. I didn't want to do this on my drive, so I found a garage with ramp hire, I'd highly recommend these guys: http://ramphigher.co.uk/ - really friendly chaps in Gravesend, Kent and had some very useful tools including bearing pullers. Here's photo of the parts,



35047AC030 UJ JOINT GEAR SELECTOR
806322080 ROLLER BEARING
806330120 ROLLER BEARING
806230170 BEARING - BOLT ON TYPE
806255010 BEARING - CENTRE DIFF FRONT
806735210 GEARBOX PROPSHAFT SEAL
33179AA030 GASKET TRANSFER CASE REAR
ST35036ST000 BUSH - GEAR LEVER STAY
633046020 SPRING PIN-BOSS JOINT

All of the above came in at 242 delivered from ICP. I also ordered some Prothane uprated shifter bushings for good measure. Also, note the different thickness m50 x 62mm shims I purchased. As Subaru modified two of the shaft bearings/races I previously read that you need to remeasure the distances (in thread above, or here + here) a few people had mentioned needing a thinner shim so I got a range just in case, turns out the 0.5mm shim was perfect.

So first step was to drain the gearbox oil (they had a raised catch can) , remove the exhaust, mounts, shields, propshaft, all pretty straight forward:



Then undo the shift linkage:




Rear casing off:



The last person used some sort of silicone instead of the OEM gasket, so it was a real pig to get the cover off after undoing all the bolts. You can't get anything in to pry the casing apart as it's a machined finish so have to very careful. Our approach was to bolt the downpipe hanger bracket back on, and hit this in the direction of the rear of the car. It came apart, but be ready with a catch can to hold the diff - it's heavier than I thought it'd be. You're left with this:



At this point, I was starting to wonder if it was these bearings causing the whine as they felt pretty good. No metal bits in the oil or signs of failure or significant wear. There was however some play on the main diff bearing itself - I haven't read about many of these failings but I'm pretty sure it was my issue.

So next was to remove the bearings+race, this was made much easier by Ramp Higher's tools + vice:





Suspected cause of my whine


New propshaft seal installed using a 36mm socket to tap it in:




Knocked this old race out, you can get good access from behind it. It has a shim behind it which replaced for a thinner 0.5mm version:



The race left on the car side is very easy to pull out, I was fearing the worst but very simple.

Next cleaned off oil, old silicone and gunk with a light abrasive scotch pad:





New bearings pushed on, mainly using the old bearing inner races to tap them on. Make sure you don't forget the shim under the diff itself. Give everything a spin to make sure it sounds/feels good:



Put the diff back in the car once I'd cleaned the silicone off the other mating surface:



Bushings and gear lever stay installed:




Case back on using the OEM gasket, and new UJ joint gear selector installed too. Getting that bloody pin back in is probably one of the hardest things on this job!



Refilled the gearbox, using a funnel and some tube with Motul Gear 300:




All in all, thanks to all the amazing information kicking around on the forum we did this in about 3-4 hours. Made much easier by the ramp and borrowed tools - I would not want to do this job on axel stands!

Diff whine has completely gone and my gear shifting feels so much better. Not sure if it's the oil change, uprated bushings or new gear selector joint....but I thought I might as well do these other jobs whilst under the car in that area and it has worked a treat. The car used to crunch in to first + second when cold, now goes in smooth like butter!

I'm sure there are loads more useful images I have, if anyone has any questions please shout.

As the pictures above show, rust was also something I needed to tackle which I did whilst I had access to the ramp for the day. Another write up coming soon!

Thanks,
Sunny

Last edited by ambassador1; 25 November 2018 at 11:16 PM.
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Old 26 November 2018, 12:16 AM
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hedgecutter
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Excellent how to. Thanks
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Old 26 November 2018, 09:44 AM
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HarryB
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I've been planning (i.e. putting off) this job for months.. mainly because it was such an issue to source the shims. Reading this:

I would not want to do this job on axel stands!
..has confirmed I'm going to get someone else to do it!
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Old 28 November 2018, 08:55 PM
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Originally Posted by HarryB View Post
I've been planning (i.e. putting off) this job for months.. mainly because it was such an issue to source the shims. Reading this:



..has confirmed I'm going to get someone else to do it!
Haha! I'm sure it can be done on stands, but is so much easier with the car in the air. Can you find a ramp hire company, like ramp it up or ramphigher? It's a very straight forward job and rewarding. How much would a garage charge for this job?

Just so you know, I did not use the Subaru shims. I sourced my own off an engineering firm. I have a few of these spare, and I also have an brand new (in packet) unused genuine STI group N gear lever support bush as I ended up using the aftermarket poly version that came with shifter bushings. Let me know if you're interested in these?

Thanks

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Old 28 November 2018, 09:46 PM
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johned
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Great stuff.
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Old 28 November 2018, 10:32 PM
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Originally Posted by johned View Post
Great stuff.
Thanks!

I did just post another thread about sorting the rust under the car but for some reason it didn't upload

In short, wire brush/flap disc, treat, paint + under seal:








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Old 28 November 2018, 10:34 PM
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