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Old Oct 21, 2016 | 11:35 AM
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Default 71 posi rearend

Any ideas on the right gear oil,just replaced the pinion seal
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Old Oct 21, 2016 | 12:25 PM
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This is what I use. It already has the proper amount of limited slip additive in it.

http://www.amsoil.com/shop/by-produc...90/?zo=1934716


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Old Oct 21, 2016 | 01:00 PM
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Originally Posted by kubs
this is what i use. It already has the proper amount of limited slip additive in it.

http://www.amsoil.com/shop/by-produc...90/?zo=1934716




good old 90 w gear lube plus gm [posi additive
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Old Oct 21, 2016 | 01:07 PM
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Originally Posted by Kubs
This is what I use. It already has the proper amount of limited slip additive in it.

http://www.amsoil.com/shop/by-produc...90/?zo=1934716
Have used it in all my differentials that call for SAE 75W-90 gear oil for years with no problems encountered. I feel it is well worth any additional expense.

Good luck... GUSTO

Last edited by GUSTO14; Oct 21, 2016 at 01:08 PM.
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Old Oct 21, 2016 | 03:33 PM
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Thanks gusto. My only issue is im only adding oil that drained when I pulled the seal. I want to top off the diff. Should I top off with the Lucas?
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Old Oct 21, 2016 | 04:56 PM
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I use Castrol 90w with GM posi additive.
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Old Oct 21, 2016 | 06:11 PM
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Originally Posted by Slickwilly00
Thanks gusto. My only issue is im only adding oil that drained when I pulled the seal. I want to top off the diff. Should I top off with the Lucas?
Really it's your call, If you know for a fact that the gear oil has been changed at some point in the past 10 years or so, or less than 50k miles, topping it off with a good name brand of the correct gear oil should be fine until the next scheduled change.

On the other hand if you don't know when the last time it was changed or if it was ever changed, I'd drain (us a hand held suction pump) the rest of the oil and refill it with your preferred gear oil and posi additive as required. In my case that would be the AmsOil.

Good luck... GUSTO
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Old Oct 21, 2016 | 06:28 PM
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Originally Posted by GUSTO14
Really it's your call, If you know for a fact that the gear oil has been changed at some point in the past 10 years or so, or less than 50k miles, topping it off with a good name brand of the correct gear oil should be fine until the next scheduled change.

On the other hand if you don't know when the last time it was changed or if it was ever changed, I'd drain (us a hand held suction pump) the rest of the oil and refill it with your preferred gear oil and posi additive as required. In my case that would be the AmsOil.

Good luck... GUSTO


I have used Mobil 1 75W-90 synthetic and Amsoil in my diff since 1990...no additive...zero issues with diff
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Old Oct 21, 2016 | 06:34 PM
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Originally Posted by GUSTO14
Really it's your call, If you know for a fact that the gear oil has been changed at some point in the past 10 years or so, or less than 50k miles, topping it off with a good name brand of the correct gear oil should be fine until the next scheduled change.

On the other hand if you don't know when the last time it was changed or if it was ever changed, I'd drain (us a hand held suction pump) the rest of the oil and refill it with your preferred gear oil and posi additive as required. In my case that would be the AmsOil.

Good luck... GUSTO
Yes. Good idea. Ill just swap out all the lube and do it right Thanks
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Old Oct 21, 2016 | 09:27 PM
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Originally Posted by Slickwilly00
Yes. Good idea. Ill just swap out all the lube and do it right Thanks
All are good suggestions....I found this recommended on the CF and used it on my last differential change. Definitely use the GM additive.


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Old Oct 22, 2016 | 08:42 AM
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Thanks green
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