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Old 01-29-2020, 01:30 PM   #7
Matt Man
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Join Date: Oct 2009
Location: Buhl, Idaho
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Re: Changing rear end fluid posi or not

Originally Posted by truckin 79 View Post
I do not have spid had to change glove box doors as hinge was gone. I just assumed most later trucks with be a one legger and no posi. I heard that if you go with Synthetic a person does not need to posi additive. Is this true?
No synthetic fluid does not replace the posi additive.

This is a open rear end:

This is a g80 rear end:

The g80 in the half ton axles (12 bolt, 10 bolt) are not very good I would be surprised that it would still be in there. My 81 came with one but when I got the truck it was not there, just had a open diff.
86 c30 crew cab dually 454/400 4/6 drop SOLD 1-8-11
1981 chevy K10 short Bed Scottsdale SOLD 10-26-2020
67 GMC Stepside Straight six/3 on the tree "The Peach"
2020 Silverado Double Cab LT Z71 5.3 8 speed Daily Driver

K10 build

The Peach build

Last edited by Matt Man; 01-29-2020 at 07:49 PM.
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