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EJ driveline conversion - changing rear diff ratio
Posted: Tue Jan 24, 2006 11:05 pm
by AndrewT
I'm installing a 4.11 AWD driveline into my L series Touring wagon.
The car currently has the standard L series 3.7 open centre rear diff.
I have a 1999 Outback rear diff, which is a 4.11 ratio open centre. It has splined sockets instead of protuding stubs.
I'm guessing I need to take the 4.11 gearset out of the Outback housing and put them into my standard L series housing (discarding the 3.7 gears) leaving me with a 4.11 open centre rear diff which will just bolt straight into my L series.
Is this the correct method?
Are there any problems going from splined sockets to stubs?
Any particular points to pay attention to?
Cheers,
a.
Posted: Tue Jan 24, 2006 11:12 pm
by SuBaRiNo
I belive (someone stop me if im wrong)
You must use the housing of the diff ratio u wish to use... so that the gears line up.
So im guessing u need to dismantle the 4.11 diff and try and only swap the axle stud parts from the 3.7 into it... should be possible.
Dave
Posted: Tue Jan 24, 2006 11:41 pm
by tim_81coupe
Yes Dave you are right.
You need to keep the pinion & crown wheels together as they wear evenly. The most trouble-free way of doing this is retaining the housing in which they both came. Not having done this exact swap I'll put forth a suggestion / educated guess:
Use the 4.11 housing, the 3.7 open centre (or take the opportunity to go LSD) the 3.7 side plates, the 3.7 stubs and the 4.11 crown wheel. Remember to put new gaskets or goo on the side plates and rear cover. Renew the side seals while you're at it too, I might have a couple lying around here somewhere with the proper flared ridge bit (name of which evades me right now).
Posted: Wed Jan 25, 2006 8:20 pm
by Ben
Each diff is shimmed to suit its particular crown/pinion, centre and side plates. If you put the 4.11 crown and pinion into the 3.7 housing, on the 3.7 centre then all you'll need to do is shim the gearset to get it running right again - gregory's type manuals explain how to do this.
Posted: Wed Jan 25, 2006 10:24 pm
by steve_rising_sun
Last time I did it I just have a groove cut for slip rings in a pair of L stubs. I sealed up the bolt hole and popped them in.
Steve
q
Posted: Thu Jan 26, 2006 9:33 am
by chriSTIan
Just bought the 3 seals 2"0" rings and metal gasket from subaru,just on
$80 the set retail.
Might b easier to find a whole 4.11 diff out of a gen 1 auto.
Posted: Thu Jan 26, 2006 10:20 am
by Ben
steve_rising_sun wrote:Last time I did it I just have a groove cut for slip rings in a pair of L stubs. I sealed up the bolt hole and popped them in.
Steve
So now they're mounted the same as the stubs in the front diff?
Posted: Thu Jan 26, 2006 10:12 pm
by steve_rising_sun
Yes if you look at the late drive shaft it has the staft on the cv with a groove cut in it. Measure how far down it is and have the groove cut on a lathe. CV places sell the clips, seal up the hole through the shaft and your in.
Steve
Posted: Thu Jan 26, 2006 11:35 pm
by seagull
I am a machinest ! & in Perth sor
Posted: Fri Jan 27, 2006 1:54 am
by AndrewT
Just noticed another slight problem...
The bit at the front-of-the-car end of the diff, where the tailshaft bolts onto it is different. The bolt holes are spaced wider apart on the 4.111 diff compaired to my L series 3.7.
If i'm going to be using the 4.111 housing I guess this part needs to be swaped out with the 3.7 then.
Posted: Fri Jan 27, 2006 9:14 am
by tim_81coupe
Could it be possible you're looking at one 90 degrees to the other? The tailshaft bolt pattern is a rectangular shape, the bolts are not evenly spaced.
Posted: Fri Jan 27, 2006 11:39 am
by AndrewT
Yeah I thought of that, its definitely different.
Posted: Fri Jan 27, 2006 6:00 pm
by steve_rising_sun
Yes you must swap the flanges. Centre punch the nut and pinion shaft first so you can rattle gun the nut to hopefully the same point.
Steve
Posted: Mon Jan 30, 2006 1:01 am
by AndrewT
Thanks for all the advice.....luckily I have found an easy way around this. A mate happened to have an open centre 4.111 which was recently removed from his L series, bolted straight into mine. Thanks Aspro!!
