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Pros and Cons of different differentials?


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11 replies to this topic

#1 Bratenstein

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Posted 25 February 2005 - 01:19 PM

I have read and read about differentials, but I am confused about the advantages and disadvantages of various options. Could someone give the pros and cons of the choices like stock, welded, limited slip, and awd?

For example, I saw posts saying you should not run 4WD on surfaces with less than 10% slippage, that welded diffs have problems turning, etc. It would be really helpful to have a comparison of what is gained and lost with each version to help decide what to do.

Thanks for your help and advice!

#2 s'ko

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Posted 25 February 2005 - 02:04 PM

Here a stab at answering.
I assume you mean rear differential.


Open/AWD (rear diffs in AWD are mostly open)
PRO: Stock set up, plentiful supply
CON: limited off-road abilities
Applications: Stock set up, trail-mild off-roading

LSD
Pro: Better off-road traction
Con Hard to find, May have wrong gear ratio
Applications: auto/rally cross, mild-hard off-roading



Welded
Pro: BEST off-road traction
Con: Requires removal of axles for street use, breaks parts due to added stress
Application: Hard Core off-roading,

#3 MorganM

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Posted 25 February 2005 - 02:12 PM

All Wheel Drive (AWD) is a designation for a type of drive train assembly; not a differential. An AWD system has differentials in it, front, center, and rear. The center one allows for 'slipage' between the front/rear differentials. This is so you can run it on dry pavement with out binding up the drive train.

Four Wheel Drive (4WD or 4x4) does not have a center differential. The transfercase locks power split 50/50 front/rear differentials. This is why you shouldnt run it on dry pavement. You can bind up the drive train and wear out parts quickly.

#4 Bratenstein

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Posted 25 February 2005 - 04:03 PM

Thanks for info. So it would appear that if I don't want to mess with disconnecting axles, the best would be an LSD for on and offroad use?

#5 MorganM

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Posted 25 February 2005 - 04:28 PM

Thanks for info. So it would appear that if I don't want to mess with disconnecting axles, the best would be an LSD for on and offroad use?


Correct.

#6 Sweet82

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Posted 25 February 2005 - 05:53 PM

I've been looking for an LSD for some time and have not found one yet.

The problem as S'Ko mentioned is it will be geared at a 3.7 so you will probably need to change out the internal gears to a 3.9.

I'm not real convinced an LSD is going to be noticable off-road. It will probably help a bit but I'm not sure it's worth the effort. I believe it's best application is on snowy pavement. If you put a wheel in the air your still going to spin it and not spin the one on the ground. It's not a locker and not positraction.

A welded diff will get you where you want to go but you still have the axle removal issue for pavement. It should take 5 - 10 minutes to pop the diff off and pull an axle off it.

My .02
Glenn
82 SubaruHummer--welded
01 Forester--limited

#7 Bratenstein

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Posted 25 February 2005 - 11:17 PM

I probably won't modify my differential at all since I live 800 miles from the nearest hill that would require 4WD (north Texas is flaaaat). But snow conditions are a concern (2 weeks or so out of the year...). Tomorrow I am going to look at a differential to see if it is LSD, so I wanted to know whether it might be worth getting. Thanks again for the helpful info.

#8 LoyaleFan

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Posted 25 February 2005 - 11:38 PM

I probably won't modify my differential at all since I live 800 miles from the nearest hill that would require 4WD (north Texas is flaaaat). But snow conditions are a concern (2 weeks or so out of the year...). Tomorrow I am going to look at a differential to see if it is LSD, so I wanted to know whether it might be worth getting. Thanks again for the helpful info.


If you are only worrying about snowy conditions for 2 weeks out of the year, I would say, "don't mess with any differential mods!" It's really not worth your time or money. Just drive sensibly in the snowy stuff. I cant imagine that you get a mass amount of snow in Texas or enough to worry about YOUR subaru having traction problems in it.

#9 grossgary

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Posted 26 February 2005 - 04:09 PM

there are also aftermarket lockers. phantom grips and detroit lockers for instance. these would be ideal in theory, though i don't know their reliability.

i have an LSD and i like it in the snow and off road. particularly helpful when pulling someone else out of the snow/mud and your rear wants to break loose. i have started slipping in deep snow while pulling someone else and feel the LSD temporarily lock up and regain solid traction.

$225 gets you a 3.7 lsd if you PM or email me.

#10 NorthWet

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Posted 26 February 2005 - 05:08 PM

...Tomorrow I am going to look at a differential to see if it is LSD, so I wanted to know whether it might be worth getting...

If it is an LSD, and the price is reasonable, there are plenty of us on the board looking for one. (Can you say resale?)

Just a thought.

#11 subieman

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Posted 26 February 2005 - 07:07 PM

I'm in the middle of converting a LSD to 3.9. It's gonna be installed on my 84 wagon. I'm doing it for the snow and rain traction. Not much for off roading but I'm sure it will help. When I get it all done and installed I'll let everyone know my outcome!

You can pick up a LSD at the local junk yard. But they are hard to come by. If you find one GRAB IT.

#12 MorganM

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Posted 28 February 2005 - 10:59 AM

there are also aftermarket lockers. phantom grips and detroit lockers for instance. these would be ideal in theory, though i don't know their reliability.


Phantom Grip is an LSD

Detroit does not make a locker for our diffs.




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