Little help replacing a suby rear diff (04 WRX) and center diff?

Got a used one already shipped out for $100 (with only 33K miles too)...just need to pull the old one out and reinstall.

While I was at it, I picked up an upgrade center diff (sti 20kg) for cheap too, figured if my diff is done, my center diff could probably be replaced as well.

Any tips or tricks out there to help me minimize time on my back in front of my apartment?

thx,

Jon

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

First of all, if you don't already have one yet, get a factory repair manual. It will help immensely.

I'm assuming you have a complete third member with the correct final drive ratio to swap? More info please. Because if you have to install just the LSD unit into your third member then it's much more complicated.
If you are swapping the whole housing and everything it's pretty staightforward. Follow the instructions in the repair manual.

The center diff is pretty easy. You may even be able to do it with the trans in the car, just depends if you can access all the bolts. I think you can. Remove the driveshaft to the rear diff (you'll have it out anyway for the rear diff). Oh yeah, don't forget to drain the trans oil. Remove the very rear diff housing cover. Not where the center diff case bolts to the trans case but the very rear most bolts you can access. Pull that housing cover off and the center diff and output shaft above it should pretty much fall on your head. The center diff slides onto the pinion shaft so it will stay in place but there's nothing keeping the output shaft from falling out which is why this is easier to do with the tranny out of the car and standing on end with a couple pieces of wood under the bellhousing to keep the input shaft off the ground or bench. But you should be able to juggle it back together in the car.

yes, I have a manual on CD, check!

and no, I don't have to open the diff case...I'm getting a full diff, case and all. So yes, I just want to swap'm out.

Thanks Dave!

Jon

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

Jon Burke Wrote:
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> yes, I have a manual on CD, check!

I say print out all the relevant pages so you can have them right at your finger tips while doing the whole job.

Next thing is to compare all the half shaft splines that the fuckers actually plug into the diff on one end and the hub on the other.
I've heard some real horror stories of Ex-spurts finding out night before the event that the new diff called for different splines by 1 spline....Ugh.
>
> and no, I don't have to open the diff case...I'm
> getting a full diff, case and all. So yes, I just
> want to swap'm out.
>
> Thanks Dave!
>
> Jon
>
> Jon Burke - KI6LSW
> Blog:
> 'Holy Shit!' @ 4:10

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

^^ check and check. I was lucky enough to find an '04, so model and year matched up unless they changed in the production line mid-stream, but I searched and no red flags came up.


someday it'll be nice to rebuild the spare I'll now have with a nice cucso or kaaz rear diff, but right now I just want to get this done for minimal $$.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

Jon Burke Wrote:
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> ^^ check and check. I was lucky enough to find an
> '04, so model and year matched up unless they
> changed in the production line mid-stream, but I
> searched and no red flags came up.

still with Subaru you never know, check the splines! plug things in to confirm so the real world can trump whatcher read of some doood tolds yas.
>
>
> someday it'll be nice to rebuild the spare I'll
> now have with a nice cucso or kaaz rear diff, but
> right now I just want to get this done for minimal
> $$.

I hear you.
Rallymech Robert "The Service Nazi" came over with his clipboard. When he says "I'm coming over with the clipboard" I chew my fingernails like Olive Oyl cause its time to start working.
Main plan is "Make it run again" then sort some of the untidier junk-n-stuff like my wiring 8).
>
> Jon Burke - KI6LSW
> Blog:
> 'Holy Shit!' @ 4:10

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Success! (on the rear diff).

Bolted off easily enough, bitch getting it lined up and back in (solo)

definitely a lot of metal shavings floating around in the old diff, and upon inspection, the end of my right rear axles splines were sheared/shaved down....just maybe 1/4" in. Doesn't seem to make any different (successful test drive), but should probably replace ASAP anyway.

This weekend will be the center diff.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

bump for some more help on the center diff....



Finally got around to upgrading the diff and drive shaft (got a deal I couldn't refuse). Anyway, I got everything unbolted on the rear tranny case (including all the shifter linkages)....got it separated about 1-2cm, and its 'loose'...but something is still holding it on.

What am I missing?

thanks!

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

Jon Burke Wrote:
-------------------------------------------------------
> bump for some more help on the center diff....
>
>
>
> Finally got around to upgrading the diff and drive
> shaft (got a deal I couldn't refuse). Anyway, I
> got everything unbolted on the rear tranny case
> (including all the shifter linkages)....got it
> separated about 1-2cm, and its 'loose'...but
> something is still holding it on.
>
> What am I missing?


You're just taking off the very rear tailshaft housing cover, right?

Here's a pic that should help:

Make sure you drive the roll pin out of the shift linkage coupler and remove it as the housing has to slide off of that shaft.

Then the center diff will come out like this:

Do not take the whole center diff housing off, you only need to remove the tailshaft cover. Everything should fall out right on your head.



Edited 1 time(s). Last edit at 08/08/2009 07:17AM by Doivi Clarkinen.

Dave, thx so much for the pics.

yes, I meant the tailcover...just taking that off, nothing else.

got the roll pin out...check.

I can pull the housing off about an inch or so, and then it just stops. feel like something is holding it back...but everything is off. definitely not 'falling on my head', which is preferable because then I'd be done w/it already.

We were thinking there may have been some other bolt or something on the side that was holding it in or something.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

nvermind...the very top bolt wasn't out all the way.

<--dumbass.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/