Rear Differential fluid

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Mar 14, 2006 | 12:14 PM

Lushman

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From: San Diego, CA

Rear Differential fluid

I am about to put on my Mag-Hytec rear differential cover and was wondering what types of differential fluids people reccomend? I live in warm weather (San Deigo. CA) and mainly use this vehicle for commuting but tow a toy hauler out to desert once and a while. Is synthetic the way to go? Do I need the friction modifier and what is that stuff? Any other suggestions would be greatly appreciated!
Thanks.

Mar 14, 2006 | 12:49 PM

FortyFords

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From: USA

use the same fluid recommended on the tag on the rear.if its a ls unit yes you need the friction modifier.
Just add more for the capacity of the mag-hytech covers.
Rich

Mar 16, 2006 | 11:59 AM

claw302

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From: EAST STROUDSBURG,PA

i put royal purple in mine.

Mar 16, 2006 | 01:43 PM

Big Orn

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From: NE Texas

Quote:

Originally Posted by FortyFords

use the same fluid recommended on the tag on the rear.if its a ls unit yes you need the friction modifier.
Just add more for the capacity of the mag-hytech covers.
Rich

Good advice right there...I second it.

Mar 16, 2006 | 02:32 PM

Bear Hunter

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From: All Over

Which is....

75W140 Synthetic. If the fluid you are using does not have the friction modifier added you need to purchase some friction modifier.

Here are three types that do not need modifier:

Redline
AMSOIL
Royal Purple

Some people say that they had to use the modifier when they put AMSOIL in...I did not. The best way to test it out is to drive "figure 8's" ...if your rear end chatters you need to add the modifier.

Capacity on a Mag-Hytec is 6 quarts. When you take your old cover off..make sure you wipe it out real good and get all that old gasket off the housting without "nicking" the surface because the Mag-Hytec uses an O-Ring to seal against the housing.

Almost forgot... don't just dump the bottle of friction modifier in there if you use a fluid that does not already have it mixed or you will end up with an Open Diff. I think the ratio is something like 4oz per 3quarts...but don't hold me to that check it out to be sure.

Last edited by Bear Hunter; Mar 16, 2006 at 02:50 PM.

Mar 16, 2006 | 05:27 PM

Lushman

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From: San Diego, CA

Thanks for the info! I am having a hard time finding the Amsoil near me and will probably need to purchase it online. Has anybody tried the Schaeffer products?

Mar 16, 2006 | 07:26 PM

bterry

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Quote:

Originally Posted by Bear Hunter

Almost forgot... don't just dump the bottle of friction modifier in there if you use a fluid that does not already have it mixed or you will end up with an Open Diff.

Why do you say that? And how's is he supposed to get in it in with out dumping it in?

Or did you mean:
..don't just dump the bottle of friction modifier in there if you use a fluid that already has it mixed or you will end up with an Open Diff..

'Cause that'd be correct.

Also, Lushman, if you end up using a add in (separately) modifier, be sure to get the rear up to temp before adding more than what is recommended. The rear will 'grab' more after it's warm. To answer your question of what is it, it's a fluid (oil) that will allow your LS differential to slip some. The more you put in, the more it will slip. It needs to slip some or you'll tear the clutches out VERY quickly.