# Differential Limited Slip Additive



## Rgrafton (Jun 26, 2012)

HI all, going to be changing out the fluid in the rear this coming weekend and was wondering if 1oz of this (K & W Chemical TRANS-X Posi-Trac Limited Slip Gear Oil Additive 402508: You?ve found the best Gear Oil at Advance Auto Parts) stuff would work. I helped my dad change out his in his truck just a week ago and he used 4oz of it, so I have some left and was wondering if it would work. 

by the way, I was going to go with the Torco 85w-140 gear oil as it has been recommended everywhere online.


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## svede1212 (Nov 1, 2005)

Use the Torco "FM" type modifier. Yes it's a "Ford" type but remember this is an Australian car with a Dana diff and that's what it takes. I would not use that stuff you show there. The correct way to add it is to add about an ounce, drive for a little bit and do some slow very hard turns in both directions. If you hear popping add a little more and repeat. Do that until it no longer pops. With a diff that isn't brand new it may take a different amount than someone else. You want as little as needed to prevent pop. The modifier makes the oil slipperier so the cones slip properly. Too much will give you one wheel peel-out.


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## Steamwalker (Mar 9, 2012)

Torco Type F additive.


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## pocketmaster (Feb 26, 2010)

svede1212 said:


> Use the Torco "FM" type modifier. Yes it's a "Ford" type but remember this is an Australian car with a Dana diff and that's what it takes. I would not use that stuff you show there. The correct way to add it is to add about an ounce, drive for a little bit and do some slow very hard turns in both directions. If you hear popping add a little more and repeat. Do that until it no longer pops. With a diff that isn't brand new it may take a different amount than someone else. You want as little as needed to prevent pop. The modifier makes the oil slipperier so the cones slip properly. Too much will give you one wheel peel-out.


Is it true that you do not need FM if you use Royal Purple ??


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## Steamwalker (Mar 9, 2012)

If you are not going to use Torco, go OEM.


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## SIXO GTO (Nov 7, 2013)

Torco RGO 85-140 2 qts & 2 oz torco Type F additive & ALL is GOOD !


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## stephen77375 (Feb 13, 2011)

Don't use royal purple, been there done that wrong type of modifier. Put it in my rear end and after about 20 miles driven sounded like the rear end was falling apart. Go to ford and get their modifier that's what I did until my torco came in. Don't get any on ya either that stuff stinks!


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## stephen77375 (Feb 13, 2011)

P.s. The K&W doesn't work either that was what I tried first before royal purple.


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