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HOW TO- WELD CENTER DIFF (LOTS OF PICS)

GolfBall

Well-known member
Joined
Aug 28, 2009
Messages
125
Location
Edmond, OK
Many opinions on weather its good or bad, this is neither, simply to show you how easy it is to do if you decide its what you want.

first off remove the end cover (11 bolts, 9 short and 2 long)

P8250996.jpg


P8250997.jpg


this is what you will see

P8250998.jpg


remove this pin on the shift fork and pull it off (keep it all together will help on reassembly)

P8251000.jpg


pull the snap ring off the VIS

P8251001.jpg


after you pull the VIS off there is a small ball bearing in the shaft (remove it and keep it safe for reassembly)

P8251002.jpg


remove the two nuts of the gears

P8251003.jpg


pull the three bolts out on the side (be sure to keep the spring and ball bearing all together)

P8251006.jpg


you should not be able to pull the second layer cover off

P8251007.jpg


there ya go... thats it

P8251008.jpg


remove your center diff

P8251009.jpg


P8251010.jpg


P8251011.jpg


P8251012.jpg


throw all this out... its not needed

P8251015.jpg


then weld it up... here is a diagram that shows it as well.

Remove everything with and X.... weld gear 6 to case 4, then weld gear 10 to case 12.

awdpic1.jpg

P8251016.jpg


P8251017.jpg


then simply reverse all the steps to reassemble and your good to go.

all wheel drive = 4 wheel drive now.

good luck.
 
Last edited by a moderator:

H05TYL

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Joined
Jun 9, 2007
Messages
752
Location
Wgtn, NZ
Good write up!

You can do all of this with the trans still in the car too.
 

cheekychimp

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Joined
Apr 19, 2004
Messages
7,333
Location
East Sussex, U.K.
This is a good write up and should be moved to How-to. I appreciate your wishes not to turn this thread into a discussion on the pros and cons of this but for the benefits of the newbies and those of us that have never done this can you list the results.

(1) How much more difficult does it make slow speed turning? Just heavier or physically impossible?
(2) Any increased wear on other transmission components?
(3) Does it only increase grip in a straight line or can this compete with a good centre LSD for cornering performance?
 

H05TYL

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Joined
Jun 9, 2007
Messages
752
Location
Wgtn, NZ
I've used one for years, so here's my take on it.

(1) Steering effort is the same, but some throttle is needed when turning sharply at walking pace. If you are used to coasting into a parking spot you will need to get used to using abit of throttle to overcome the cars resistance to turning. You can get away with not using the handbrake just by turning the steering to one side, the weight of the car alone isn't enough to overcome the grip of the inside rear tyre.

(2) The only wear issue I've noticed is once one of the front CV's started clicking it got worse quicker than it probably would've with a stock centre diff.

(3) A locked centre diff will cause more understeer on turn in compared to a stock viscous diff, it will also cause more oversteer on corner exit - dependant on setup. Normally the rear tyres turn slower when cornering as they travel a shorter distance, with the locked centre they must turn at the same speed as the fronts, so once the car has overcome it's initial resistance to turn in it will infact turn sharper as the rear tyres must slide (slightly) to follow a similar line to the fronts.
It's very much dependant on setup and driving style whether this is better or worse than stock.
In low traction situations (gravel/dirt/wet) I found it makes the car more predictable once it starts sliding.

I haven't driven anything with a plate or torsen centre diff, but I suspect either would be superior to a locked centre - at a higher cost obviously.
 

GolfBall

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Joined
Aug 28, 2009
Messages
125
Location
Edmond, OK
well i was gonna reply but dang, he took care of it very thoroughly. i dont think i have much to add. /ubbthreads/images/graemlins/smile.gif

here is a great video that made me wanna weld my diff even more. (esp since im a straight line racer)

compare this (non welded)

click

to this, (welded)

click
 

mitsuturbo

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Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
As i said in the how-to...

if you have any doubts about doing this mod, drive a vehicle that behaves similarly
My 98 montero sport 4wd (not A4WD) when put into 4wd behaves like a car with a welded center diff.. you can feel it bind when you make a tight turn. It's REALLY pronounced when you make a U turn or go into a drive through.

Other vehicles do this as well. I'm not sure of all of them, but i know the Montero Limited has a pushbutton Center Diff lock.
 

DynastyLCD

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Joined
May 12, 2006
Messages
761
Location
Harwinton, CT
my take:

1) it resists momentum during low speed manuvers, most noticeable while turning. as previously stated, if you are coasting at low speed, then cut the wheel hard, it will slow the vehicle down quickly. steering effort is the same.
2) going by what is logical to me, if the differential isnt rapidly switching power output from front to rear, and they always have the same power going to them, that would equal less drivetrain shock, which equals less broken parts.
3) couldnt answer this, i can tell you though its a great upgrade over the stock setup, thats for sure.

come to think about it, i dont think id spend the money on a real differential after doing this.

great write-up, fastjetta!
 

alansupra94

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Mar 3, 2010
Messages
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Location
Wayne,NJ
Oh man all the pictures are down /ubbthreads/images/graemlins/frown.gif

MORE BANDWIDTH!
 

alansupra94

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Mar 3, 2010
Messages
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Location
Wayne,NJ
Now I guess my next question is how would this react with a non-lsd rear end? Would you guys recommend a lsd rear end and lsd front?

I really want to make my VR4 a beast in the winter.
 
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mitsuturbo

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Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
With open diffs all around, your car will likely go straight in the snow/ice.
With a welded center and LSD rear, it WILL go sideways. With a LSD front added, i'd imagine it would go whichever direction it wishes.
My car handled a LOT worse in snow once i added the LSD 4 bolt rear. It's predictable, but not nearly as predictable as open diffs all the way around.
 

alansupra94

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Joined
Mar 3, 2010
Messages
1,909
Location
Wayne,NJ
Oh okay.

Reason I asked is in this thread, fastjetta posted up 2 videos of a car with and without an open diff launching. I was curious to know if you need an LSD in the front and rear in order to replicate that.

So basically, having a welded center diff will have all four wheels spinning at the same speed?
 

GolfBall

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Joined
Aug 28, 2009
Messages
125
Location
Edmond, OK
i know have a welded center and rear diff...

welded center diff is nothing... welded rear you notice alot /ubbthreads/images/graemlins/smile.gif hahaha.
 

desant78

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Joined
Jun 23, 2010
Messages
732
Location
Clarksboro, NJ
Quoting alansupra94:
Oh okay.

Reason I asked is in this thread, fastjetta posted up 2 videos of a car with and without an open diff launching. I was curious to know if you need an LSD in the front and rear in order to replicate that.

So basically, having a welded center diff will have all four wheels spinning at the same speed?



if you have an open front and rear diff but welded center diff...that does not ensure all four wheels will have the same speed. If the either of the front tires start to slip...the torque will drastically decrease on both front tires...so the tires w/ less traction (slipping tire) will spin faster as the tire with grip will produce a low torque and seem to not move, irrelevant if you have a welded or open center differential. hope that helps!
 

codeofdastreets

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Joined
Aug 30, 2008
Messages
65
Location
Palm Harbor FL


the left diff is stock, the right one is the tre welded diff kit.
 
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this would be my first time on the trans. i know this would help me out alot. i always sent them out to get done.

my question would be; do i have to line up the spline then weld? or can i just weld away?
 

codeofdastreets

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Joined
Aug 30, 2008
Messages
65
Location
Palm Harbor FL
I would line it up just to make sure there is no problems..
 

hello good day just looking for a little info when reassembling the center diff after it is welded do i put back the the parts that is marked x in the diagram the small spyder gears and the cross etc etc or are these left out thnks in advance
 
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DynastyLCD

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Joined
May 12, 2006
Messages
761
Location
Harwinton, CT
when you are all said and done, the top and bottom gears are welded to the case, and nothing else is needed. everything marked X gets thrown out.
 
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