Replacing a fubar center differential

[99lego]

So after a lot of looking I found a center diff for $200.

It wasn't easy as nearly everyone I spoke with would not divorce the diff from the trans....but finally I lucked out.

 

Now that I have the part I was considering replacing the bearings that are in the case:

 

 

More specifically I was definitely going to replace whats referred to as #28 in the diagram and was considering the bearing located behind the transfer drive gear #32. I was also entertaining the idea of doing both bearings, #24 & #26, on the transfer driven gear.

But...having never torn into the case before, and having no idea whatsoever about the worth while of doing all these bearings while i'm in there, I have come to you with my plight.

 

Subaru shockingly enough has all four of these parts sitting on the shelf at the local dealer.

 

So I ask the question what would you do in this situation?

Edited November 10, 2011 by 99lego

[Fairtax4me]

I've never heard of anyone replacing the bearings in the tail housing. I had one in my old transmission that was a little loose, but I decided it wasn't worth replacing. Plus a few of them are more difficult than it's worth because they're pressed on, and chances are they aren't bad anyway.

 

When you get it apart, see if any feel like sand paper or have a lot of play, if not then I'd leave them alone.

[GeneralDisorder]

Don't bother replacing those bearings. They aren't a failure item on the 5MT's. The input shaft bearings on the transmission main shaft will go out long before those do. There's just not enough stress on them to worry about. Needlessly expensive.

 

GD

[99lego]

Don't bother replacing those bearings. They aren't a failure item on the 5MT's. The input shaft bearings on the transmission main shaft will go out long before those do. There's just not enough stress on them to worry about. Needlessly expensive.

 

GD

 

 

I appreciate the feedback.

 

Right now the car has nearly 200k on the drivetrain, 100k of which the unibody has been blocked down 2" while the top hats have been perched on 2", and she's been running on 28's.

I feel that the added stress would dictate a bit of preventative maintenance. I mean I'd feel that mitigating any potential for failure would save me in the long run...no?

 

... a few of them are more difficult than it's worth because they're pressed on, and chances are they aren't bad anyway.

 

When you get it apart, see if any feel like sand paper or have a lot of play, if not then I'd leave them alone.

 

 

So when you say more difficult than it's worth what are you getting at?

 

After researching diff bearings I've found on a few boards that they can be equally responsible for causing noise, vibration, and other glorious things associated with a bad diff / concern:

http://forums.nasioc.com/forums/showthread.php?t=1170285

 

I feel that more feedback would be helpful here.

Edited November 8, 2011 by 99lego

[GeneralDisorder]

I appreciate the feedback.

 

Right now the car has nearly 200k on the drivetrain, 100k of which the unibody has been blocked down 2" while the top hats have been perched on 2", and she's been running on 28's.

I feel that the added stress would dictate a bit of preventative maintenance. I mean I'd feel that mitigating any potential for failure would save me in the long run...no?

 

With that many miles on it and the lift/tire stress - I question the replacement of the rear diff at all without also splitting the case and checking everything out.

 

When the 5MT's fail - it's the rear input shaft bearing that goes. If you are going to replace bearings then I highly sugest you split the case and replace that one. None of the other bearings really matters if you are going to leave that one with 200k on it. They won't be the first to fail and typically they are just fine even after a tranny is nearly destroyed inside.

 

Inspect them. Blown them out with solvent and spin them - if you feel any roughness then replace. But don't just replace a bunch of bearings that aren't failing for no reason - especially when the main transmission has 200k on it. Chances are that they are fine and they don't need to be renewed because the rest of the tranny will amost certainly blow up first.

 

GD

[99lego]

With that many miles on it and the lift/tire stress - I question the replacement of the rear diff at all without also splitting the case and checking everything out.

 

GD

 

Ok....so just to be clear this is the center diff not the pumpkin.

 

Inspect them. Blown them out with solvent and spin them - if you feel any roughness then replace. But don't just replace a bunch of bearings that aren't failing for no reason - especially when the main transmission has 200k on it.

 

GD

 

You were right.

They were all totally fine and will be returned to the dealer tomm.

 

Chances are that they are fine and they don't need to be renewed because the rest of the tranny will amost certainly blow up first.

 

GD

 

I can't wait to blow up this tranny so I can move on to shorter gears but.....I slapped that center diff in today and once she was all buttoned up and back on the road I'm be willing to bet she'll go another 100k on 4" w/ tires before she needs anything else (most likely a new diff again!!!).

 

 

Really though she's running like nobody's business now. That is: no whine / whir / change in audible pitch after the diff warms up. The car no longer lunges / lurches / hesitates / pauses when you let off and also is free of any binding even with the 28's locked in both directions.

 

Now for the gory stuff:

 

Separating the case was cake with a flathead but, when I pulled the rear cover off the viscous coupler came with it...

 

 

That is the Phase II center diff divorced the viscous coupler. From what I understand the fluid within the VC is blue. What was drained out today was a milkshake....just like how it was ~6k ago when it was drained after the pass side CV boot fragged grease all over the block and was replaced.

 

So I fragged an entirely sealed unit within a sealed unit and did ~6k with her. I dunno if I should or here.

 

Who else has this happened to?

Edited November 10, 2011 by 99lego

[99lego]

I can't be the only one who's had this happen to them. Who's out there?