Author Topic: Posi Oil  (Read 3594 times)

Offline Ghazi67

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Posi Oil
« on: December 02, 2009, 04:08:19 am »
Hello ;

While working under my K15 .. I found a little leak in rear diff. cover.
I did purchase the cover gasket and diff. oil. I was surprised that it has a posi unit !!!!

Which oil type/grade should I use ( if I am not going to use GM's ) ?
&
Is it usual to find posi unites underneath these trucks ?? ( mine is a K15 )

Chevy Head from Overseas
Old riders : 74 w/LT1 Blazer & 82 K15.
Current rides : 66' Impala SS & 85 GMC 1500

Offline VileZambonie

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Re: Posi Oil
« Reply #1 on: December 02, 2009, 05:05:18 am »
Just get the limited slip adative and you can run 80w90
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Ghazi67

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Re: Posi Oil
« Reply #2 on: December 04, 2009, 12:56:11 pm »
Vile ..

Thanks for the tip ...
what about 75W140 grade !?
They do use it here for sever duty vehicles... do U think this will replace the GM Additive ?
Chevy Head from Overseas
Old riders : 74 w/LT1 Blazer & 82 K15.
Current rides : 66' Impala SS & 85 GMC 1500

Offline VileZambonie

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Re: Posi Oil
« Reply #3 on: December 04, 2009, 01:33:51 pm »
No it won't replace the additive
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              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Captkaos

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Re: Posi Oil
« Reply #4 on: December 05, 2009, 12:15:22 am »
You HAVE to have the additive.

Offline Ghazi67

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Re: Posi Oil
« Reply #5 on: December 11, 2009, 05:33:12 am »
VileZambonie  &  Captkaos

Thanks Gentelmen
Chevy Head from Overseas
Old riders : 74 w/LT1 Blazer & 82 K15.
Current rides : 66' Impala SS & 85 GMC 1500

Offline fighterofwars

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Re: Posi Oil
« Reply #6 on: January 01, 2010, 06:44:46 pm »
Sorry to bring this thread back, I just changed the rear diff oil in my 87 K20. It has the 16 bolt semi-floater with the G80. I read here that you need to use the additive. So I picked up a bottle of this stuff call Trans X for limited slip, posi rear ends. And just a few minutes ago I read this.

The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life. On another website.

Do I need to drain the oil and just put in straight oil with no additive? Thanks.

Offline VileZambonie

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Re: Posi Oil
« Reply #7 on: January 01, 2010, 07:58:32 pm »
I wouldn't be too concerned with it... Drive it for a while and change the fluid again. It will be nice n clean  ;D The friction modifier is intended for clutch and cone type lsd's
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10