Settin' up Subie Front diff preload?

hey....I haven't started a thread in this section in a long time, see how smaht rally anarchy has made me???!!


anyway....final steps of putting the new tranny together and I can't for the life of me find any specs in the manual for setting the pre-load on the side retainers holding the front diff together.

adjusting is no problem, but what's the base-line setting for how tight these suckers should be holding the diff?


shop manual just says:

Quote

B: INSTALLATION
1) Install the differential side retainers using ST.
ST 499787000 WRENCH ASSY
2) Install the bearing outer race to transmission
case.
3) Install the differential assembly.

Sure...so I just 'install' the side retainer, eh? thanks for all the friggin' detail.

Quote
Jon Burke
hey....I haven't started a thread in this section in a long time, see how smaht rally anarchy has made me???!!


anyway....final steps of putting the new tranny together and I can't for the life of me find any specs in the manual for setting the pre-load on the side retainers holding the front diff together.

adjusting is no problem, but what's the base-line setting for how tight these suckers should be holding the diff?


shop manual just says:

Quote


B: INSTALLATION
1) Install the differential side retainers using ST.
ST 499787000 WRENCH ASSY
2) Install the bearing outer race to transmission
case.
3) Install the differential assembly.

Sure...so I just 'install' the side retainer, eh? thanks for all the friggin' detail.

What kind of bearings? Ball? Taper roller?
My gawd jim I can't perform miracles with these tools!

How about piccies compooter whiz-boy?
What did you set the diff preload to--or breakaway torque?

Youse gots power steering so you don't have to be a beeeeeg pussy about it.

Taper bearings, although the manual does call them a roller bearing....here's pics of the original ones.









Diff pre-load/breakaway torque is set from the factory, no adjustment necessary there. (carbonetic LSD)

I don't have any other pics on me....I'm heading over there tomrorow night to try and finish everything up, so was hoping to have an answer before then.

Actually....here's the manual:
http://ken-gilbert.com/wrx/04impreza/imp04_trans_4-3.pdf

scroll down to page 102....section B and you'll see the instructions I cut and pasted above.

The next pages 103 to 106 you can skip because that's installing the OEM open diff and setting that up. But page 104 discusses 'installing the roller bearing' onto the diff.

Page 107 gets into setting the backlash for the ring and pinion, and you can see pics of the outside of the case and the side retainers and the stupid 'special tool' and how to adjust.

It even covers how much backlash is adjusted by turning the retainer 5 degrees with the stupid tool, but it never gives you a 'reference' point to start at.



Thanks JV, for any help/insight.

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Jon Burke
Taper bearings, although the manual does call them a roller bearing....here's pics of the original ones.









Diff pre-load/breakaway torque is set from the factory, no adjustment necessary there. (carbonetic LSD)

I don't have any other pics on me....I'm heading over there tomrorow night to try and finish everything up, so was hoping to have an answer before then.

Actually....here's the manual:
http://ken-gilbert.com/wrx/04impreza/imp04_trans_4-3.pdf

scroll down to page 102....section B and you'll see the instructions I cut and pasted above.

The next pages 103 to 106 you can skip because that's installing the OEM open diff and setting that up. But page 104 discusses 'installing the roller bearing' onto the diff.

Page 107 gets into setting the backlash for the ring and pinion, and you can see pics of the outside of the case and the side retainers and the stupid 'special tool' and how to adjust.

It even covers how much backlash is adjusted by turning the retainer 5 degrees with the stupid tool, but it never gives you a 'reference' point to start at.



Thanks JV, for any help/insight.

Jon, I'm horribly busy, you cut and paste the thing, I won't follow links to some maze Cut and Paste.
I betcha it's a dumb tool like for uses which means you'll have to fake it somehow. I used one of the bearing holders with shitload of little tooofies to turn the one in the case---after suitable mods---welding a socket on

EDIT: and to be clear, we never actually REMOVED the retainers from their OEM location. we put everything in and adjusted the pinion shaft with different shims and got a good tooth pattern, its just a little high and there's just a little bit too much backlash, so we're not starting from scratch, but we don't want to start moving things back and fourth until we figure this part out.

Quote
john vanlandingham

Jon, I'm horribly busy, you cut and paste the thing, I won't follow links to some maze Cut and Paste.
I betcha it's a dumb tool like for uses which means you'll have to fake it somehow. I used one of the bearing holders with shitload of little tooofies to turn the one in the case---after suitable mods---welding a socket on

its a PDF, so all I can give you is a link, can't cut and past images from a PDF. It doesn't really matter, because the instructions aren't in there. turning the stupid thing w/o the 'special tool' isn't the issue...the issue is, what's the damed proper pre-load? Once we get that, then adjusting the diff back and fourth is easy, but, "where do we star from" is the question.


so, the instructions go like this:


Left side retainer:

Quote

B: INSTALLATION
1) Install the differential side retainers using ST.
ST 499787000 WRENCH ASSY
2) Install the bearing outer race to transmission
case.
3) Install the differential assembly.

right side retainer:

Quote

2. HYPOID GEAR BACKLASH
Adjust backlash by turning the holder in right side
case.
ST 499787000 WRENCH ASSY
NOTE:
Each time holder rotates one tooth, backlash
changes by 0.05 mm (0.0020 in).

OK....but don't you need a reference point to start from? None is listed in the manual besides these vague instructions.



Edited 1 time(s). Last edit at 02/16/2011 04:40PM by Jon Burke.

In the 2002 wrx MT manual, page MT55 and MT56 there is a explaination. There is no "number" for the preload of the brgs. The "preload" is basically 1/2 turn of the side plate after contact, you better find that part in the manual.

Hey on the Carbonetic diff, what ever you do don't just stick it in "out of the box", if you do the carbon pucks will fail (and fuck everything up)within 50 stage miles. You will need to reorientate the plates to reduce the load. The carbonetic action is real nice and smooth but unlike a metal plate LSD the carbon plate pucks become grippier the hotter they get and will rip themselves apart, if that doesn't happen first the entire drum will explode, blow the end right off it.



Edited 1 time(s). Last edit at 02/16/2011 05:46PM by Gravel Spray.

The 2002 and '95 manual that I have has Standard backlash: 0.13 - 0.18mm but I think I did my bearing preload by feel. not sure if that makes me a bad person.

Quote
Gravel Spray
In the 2002 wrx MT manual, page MT55 and MT56 there is a explaination. There is no "number" for the preload of the brgs. The "preload" is basically 1/2 turn of the side plate after contact, you better find that part in the manual.

Hey on the Carbonetic diff, what ever you do don't just stick it in "out of the box", if you do the carbon pucks will fail (and fuck everything up)within 50 stage miles. You will need to reorientate the plates to reduce the load. The carbonetic action is real nice and smooth but unlike a metal plate LSD the carbon plate pucks become grippier the hotter they get and will rip themselves apart, if that doesn't happen first the entire drum will explode, blow the end right off it.

Thanks Peter, that's what I was looking for....I can't seem to find that in my 2004 manual, but I'll look through it again. the 2002 and 2004 trannies are very similar, so I'd bet real money its the same.


Regarding the diff...thx for the tip as well, I'll email Kiyo over there and see what he says. I'm pretty sure we didn't adjust any plates on my rear diff and its fine. I just did the whole 'figure 8s' for 20 minutes, change fluid, and repeat, for the break in. Zero problems so far, its actually pretty quiet.

GREAT....found the '02 manual and it was exactly where you said....pages 55-56, which is the 'transmission case assembly' section.

Now, why it would be there and not in the 'front differential assembly' section, I have no idea (its not even referenced, at least that would make it a little bit easier).

meh....Japanese.....anyway, looks pretty straight forward. 'preload' is just one additional 'notch' from first contact, so that's basically hand tight from there.

Quote
Jon Burke

Quote
Gravel Spray
In the 2002 wrx MT manual, page MT55 and MT56 there is a explaination. There is no "number" for the preload of the brgs. The "preload" is basically 1/2 turn of the side plate after contact, you better find that part in the manual.

Hey on the Carbonetic diff, what ever you do don't just stick it in "out of the box", if you do the carbon pucks will fail (and fuck everything up)within 50 stage miles. You will need to reorientate the plates to reduce the load. The carbonetic action is real nice and smooth but unlike a metal plate LSD the carbon plate pucks become grippier the hotter they get and will rip themselves apart, if that doesn't happen first the entire drum will explode, blow the end right off it.

Thanks Peter, that's what I was looking for....I can't seem to find that in my 2004 manual, but I'll look through it again. the 2002 and 2004 trannies are very similar, so I'd bet real money its the same.


Regarding the diff...thx for the tip as well, I'll email Kiyo over there and see what he says. I'm pretty sure we didn't adjust any plates on my rear diff and its fine. I just did the whole 'figure 8s' for 20 minutes, change fluid, and repeat, for the break in. Zero problems so far, its actually pretty quiet.

Email, shme-mail.
Lissen to what Peter says!
Instead ask about doing what he suggested.
Ask a open ended question you'll get some general generic answer.
A guy who has seen the buugers blow the fuck up is speaking to you..

Hint: listen to people with specific experience.

Quote
john vanlandingham


Hint: listen to people with specific experience.

you think I'm not?

I think its funny that because I'm taking Pete's feedback back to my guy at the manufacturer, you think I'm not listening. how's that? :p



don't worry JV, I'm on it I promise I'm smarter than you give me credit for!

Kevin, Feel is good, once you do a few gearboxes you kinda develope the "touch".

Jon, the rear diff, have you tore it down and had a look at the plates? On the front, they get a tad bit more abuse due to the weight on the front and the steering forces more diff action so it will get hotter. Kiyos a good guy, very accomidating but I'll tell you what, they've got a warehouse full of product to move, so thats his MO.

One thing you can do after installation and break in is to get the diffs hot as hell, like work them HARD, jack up the car, hold one side of the axle from moving and see if the breakway T is massive, or even LOCKED, if so you will have a failure. The best way to deal with this is to reduce the available friction surface. We have had to stack 2 of the 3 steel plates on the outside, then just inside of that stack 2 of the 3 carbon puck plates together, then teh steel, then the last carbon plate against the cam ring. This will reduce untimate lock value by 33%. And don't use any oil but the Carbonetic stuff....I see you have been using the redline shock "poof" bad stuff, bad bad bad!



Edited 1 time(s). Last edit at 02/17/2011 10:46AM by Gravel Spray.

Quote
Gravel Spray
K And don't use any oil but the Carbonetic stuff....I see you have been using the redline shock "poof" bad stuff, bad bad bad!

Use that and you'll have a Shock when your gears go Poof!

And another shock when you when you're money goes POOF when you fix the box.

One word for shock poof oil: excessive aeration

Quote
john vanlandingham

Quote
Gravel Spray
K And don't use any oil but the Carbonetic stuff....I see you have been using the redline shock "poof" bad stuff, bad bad bad!

Use that and you'll have a Shock when your gears go Poof!

And another shock when you when you're money goes POOF when you fix the box.

One word for shock poof oil: excessive aeration

yes, like beat egg whites! Plus they have blended in parafin wax(the shock "proof", under prolonged centrifical force it become separated and starts to gather in needle brg cages, packes them solid and acts as a squeegee. It also clogs the syncro grooves so they float on the cone, shit is useless.