normal rear-end or limited slip (identification hints)

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normal rear-end or limited slip (identification hints)

Postby rhyolite » Thu Feb 19, 2015 5:45 pm

Hi guys,

I'm planning to take of the rear end axle cover this weekend cause it's leaking.
Clean it up, fix the gasket, etc, etc, yada, yada...

But I need to refill it with new oil, how can I tell I have a limited slip diff, or a "normal" diff ...
Is there any way to identify it ? (numbers, codestamp, the way it looks?)
I've read it normal/LS diffs need a different kind of oil.

It's a 1975 pontiac astre SJ Safari ... any help would be highly appreciated, would hate to put in the wrong oil ..
The manual only states the cars could be equiped with both versions.

Thanks,

Tiemen
The dutcH-bodies
- 1974 Vega hatchback
- 1975 Astre SJ Safari wagon
- 1975 Astre hatchback

- 1991 Jeep Wrangler YJ
- 1993 Jeep chief Cherokee XJ
- 1998 Chevrolet Camaro Y87 V6 3.8
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1975 Pontiac Astre


Re: normal rear-end or limited slip (identification hints)

Postby BadBowtie » Thu Feb 19, 2015 6:58 pm

I dont know the specifics of things to look for on the differential, but a good way to check is to jack the back wheels off the ground and turn the one wheel, if both wheels turn in the same direction you have a posi/limited slip, if they turn in the opposite direction then its an open diff.
James

1975 Vega GT sbc, Microsquirt w/Edelbrock MPFI, M21 4-speed and Ford 9"
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Re: normal rear-end or limited slip (identification hints)

Postby rhyolite » Fri Feb 20, 2015 10:02 am

Ooohh that's simple :) Even I can figure that out :)
Thanks for the answer !!

Tiemen
The dutcH-bodies
- 1974 Vega hatchback
- 1975 Astre SJ Safari wagon
- 1975 Astre hatchback

- 1991 Jeep Wrangler YJ
- 1993 Jeep chief Cherokee XJ
- 1998 Chevrolet Camaro Y87 V6 3.8
rhyolite
 
Posts: 163
Joined: Tue Nov 05, 2013 2:06 pm
Location: The Netherlands

1975 Pontiac Astre

Re: normal rear-end or limited slip (identification hints)

Postby cosvega76 » Fri Feb 20, 2015 10:11 am

Tiemen,

As long as you have the cover off, look at the differential through the opening where you can see the spider gears. If all you see are spider gears, it's an open. If you see a pair of wavy, flat plate springs between the center pin and the side gears, it a posi (provided it's an OE or cone/friction plate style posi).


Chuck
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Re: normal rear-end or limited slip (identification hints)

Postby cjbiagi » Fri Feb 20, 2015 7:43 pm

While there are different style limited slip carriers and I am not sure if yours is a 6.5" or 7.5", most GM cone style carriers should have some springs inside like this. There is usually a metal tag attached to the one of the bolts holding the cover on indicating it's a posi, although these could easily have either been removed or added by somebody.
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Clyde.........75 Monza 2+2
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