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LSD diff problem... please help :(

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Old 11-30-2014, 09:23 PM
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Unhappy LSD diff problem... please help :(

Hi
my car recently have a problem with it's lsd...
i changed the oil and add limited slip , but no difference at all...
in the sides , when you accelerate , just one of tires spins
i can't do donuts anymore




Old 11-30-2014, 09:51 PM
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Looks like an Auburn LSD. What year car ? How many miles on it ?
When an Auburn wears out past the point of serviceability/useability,the cone clutches are so worn out that they can't supply the proper friction(as cone clutches wear out,they move away from each other,resulting less and zero spring force for the cone clutches).The differential begins to act as an open(non-lsd).
As a last try,refill with new fluid and use the GM friction modifier.
Old 11-30-2014, 11:36 PM
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My last resort to save my worn Auburn was to change the oil and NOT use friction modifier, I wanted the cones to grab more. Doing that improved the posi some but long term you'll need a new posi unit.
Old 12-01-2014, 06:03 PM
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thanks for replies !
the car is 1997 camaro z28 and 70000 kilometers on it
i bought it on 50k and the problem starts recently about 69K !
i should notice that i made rear suspension lower , does it have a big effect?
it's random... sometimes the LSD works , in straight acceleration it's ok and i feel it
but in corners sometimes it's work , and sometimes doesn't work , specially in wet road
the fluid was never changed before and it was black
maybe now i am using bad or fake fluid? i also hear gears noise after fluid change...
85W-90 and the weather is cold

i should notice that too , when i lift the car onto jack, i can pull and push rear tires inside and outside a little... maybe a big Clearance...

the important thing is there is no parts in my country and i have to fix it without any OEM parts , maybe another car parts fits...

what i should to do?

Last edited by Arsalan Yazdani Ford; 12-01-2014 at 07:06 PM.
Old 12-01-2014, 06:35 PM
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Lowering the rear suspension should have no effect on LSD,but it will change pinion angle.
Fluid does get black in an Auburn from normal cast iron particle wear.
You're asking a lot to want the LSD to function cornering as then it has two functions to perform,spider gears functioning due to turning and LSD.
How much is that push/pull clearance/movement ? A little in/out is normal for the c-clips.
Your carrier is an Auburn 7.5"/7.635" for GM 10 bolt with 28 spline axles. The important factor is the 28 spline for the axles. Chevy/GMC S10 trucks and Blazers also used that carrier,not all had/came with LSD. And the earlier ones were for 26 spline axles,later ones had 28 spline axles.
Automatic or 6 speed ? Asked to determine your rear gear ratio. 6 speed would be 3.42,auto could be 2.73 or 3.23. Is the option code sticker still with the car ?
Old 12-01-2014, 07:02 PM
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You mean 90's blazers? we have a lot of 70's GM products in here but not any 90's ! but more than 95% non lsd
auto tranny .... yes i have a picture of the sticker
the movement in driver side is more than passenger side... i think this is not normal !
but no differents in left or right corners at all

i believe that my LSD works better in normal acceleration , in hard accelerations at corners it just spin one of tires
it was ok before this problem


Old 12-01-2014, 07:15 PM
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Thanks you for showing the stickers !
GU2 is 2.73 rearend gear ratio. That means your carrier is 2 series. You won't find a carrier from a vehicle as they would be 3 series for 3.73 and 4.10 gears.
G80 is the limited slip(LSD) carrier.
NW9 is the traction control option. You should have a switch on dash to turn off traction control. With it off,does that change the performance in cornering and in rain? Traction control is there to prevent dangerous situations !
Old 12-01-2014, 07:22 PM
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I don't know if it really means anything, but Auburn EXPLICITLY tells you to use a MINERAL BASED gear oil ONLY with 4 ounces of the friction modifier.

I don't know if this has any real bearing on anything, if they actually designed their units around mineral gear oils, or if they just NEVER bothered to test any synthetic based gear oils in their various diffs (like ALL of Eaton's diffs), so they cannot backup the performance when using synthetics.
Old 12-02-2014, 12:18 PM
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The GM part number for that LSD carrier is 26036756,Auburn part number 542041.
Old 12-02-2014, 03:10 PM
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thanks again
i've changed the oil this morning and i think this was helpful
the new oil is 85w140 GL-5 but didn't use additive
i've tested the LSD in the corners and it seem's to be OK
i should to test it some more times to be sure
the noise are gone i think

this is the oil i've changed few days ago... GL-4 and i think this was crap !!






new oil (sorry for persian language , they are the names and not important )



i will send you the result
Old 12-02-2014, 04:03 PM
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^^^THAT could have done it!

That L-M fluid is NOT crap, it is just NOT the correct fluid for hypoid differentials/rear axles.

ALWAYS, ALWAYS ONLY use a GL-5/GL-5+ gear oil for any rear axle which would go under these cars!!

The GL-4 fluids do not contain the correct extreme pressure additives (among others) which is NECESSARY for the proper (and QUIET) functioning of our diffs/axle gears.
Old 12-02-2014, 07:29 PM
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NW9 is the traction control option. You should have a switch on dash to turn off traction control. With it off,does that change the performance in cornering and in rain? Traction control is there to prevent dangerous situations !
Yes , when i turn the car on , the first thing i do is turn the ASR off
it would not let the wheels spin , i don't like it , even in raining

That L-M fluid is NOT crap, it is just NOT the correct fluid for hypoid differentials/rear axles
Sure but i think that was a fake version of L-M ! cuse there are so many fake oil's here unfortunately
Old 12-03-2014, 03:44 PM
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i've tested the LSD many times and it's really OK ! thank you guys...
check my new Thread here
https://ls1tech.com/forums/automatic...l#post18555172
Old 12-03-2014, 03:44 PM
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i've tested the LSD many times and it's really OK ! thank you guys...
check my new Thread here
https://ls1tech.com/forums/automatic...l#post18555172
Old 12-04-2014, 07:39 PM
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Oops sorry i forgot to ask
if i wanna change my crown wheel & pinion, does it same with 1970's blazer k5 or suburban?
and what do you think is the best gear ratio with stock engine (lt1) and gearbox (4l60e) for 1/4 mile?!

Last edited by Arsalan Yazdani Ford; 12-04-2014 at 07:50 PM.
Old 12-04-2014, 08:36 PM
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your first picture in this thread shows the housing with the Auburn LSD carrier with a ring gear. Is that ring gear what you're referring to as 'crown wheel' ?
Old 12-04-2014, 08:43 PM
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this is the Richmond page that shows what GM vehicles have the same size gearset for the 7.5"/7.625" rears.

http://www.richmondgear.com/pdf/Rich...n1.pdf#page=27
Old 12-04-2014, 08:53 PM
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since you have 2.73s',which are on a 2 series carrier,you can only use the gearsets which are manufactured for a 2 series carrier. those gearsets are referred to as 'thick'. 4.10s and 4.56s' are too much for an A4 automatic.
Old 12-05-2014, 06:52 AM
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If you happen to find a set(ring AND pinion) in the range of 3.23-3.73,you will still have to set pinion depth and 'lash'. Without setting those two parameters,whatever set you install will be noisy and wear out very quickly. And any wear(particles) from the ring and pinion will cause premature wear in the LSD,pinion and carrier bearings,and axle bearings.
Old 12-06-2014, 06:55 PM
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Is that ring gear what you're referring to as 'crown wheel' ?
yes


this is the Richmond page that shows what GM vehicles have the same size gearset for the 7.5"/7.625" rears.
Thanks !! this is exactly what i needed






i think i can find 1990-1993 chevrolet s10 pick-up here !
it does'n mention the pick-up word , you think does it fit my car?
there are few 4cyl chevrolet s10 here like this



4.10s and 4.56s' are too much
you mean 3.23-3.73 is better for 1/4 mile for my car?

One other thing, can i just change the pinion? for example my diff is 15-41, can i just change the pinion with a 11-41 or 9-41 pinion and do not change the ring?
some body told me , when they made ring and pinion in factory , they tested them together and you can not change only one of them , is that true?

Last edited by Arsalan Yazdani Ford; 12-06-2014 at 07:22 PM.


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