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Aug 11, 2021 | 03:36 AM

RonC80

Thread Starter

Mountain Pass

Joined: Feb 2009

Posts: 215

Likes: 6

From: Delhi NY

Rear diff

So what does everyone use for the rear differential fluid? I have a leaking cover so I am replacing it and new gasket. Does Ford use synthetic from the factory? If they don't and I would like to put synthetic in it . What adverse effects happens if I don't get all the old out?
. 08 f250 super duty 5.4 4x4.
What weight would you all recommend? I live in upstate New York. Not any off road use except maybe hay field to pick up a deer that I don't feel like dragging..
. Again I'd like to thank everyone with the help with fuel pump issue.

Aug 11, 2021 | 07:04 AM

rvpuller

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Joined: May 2004

Posts: 6,507

Likes: 897

From: Home Base Nebraska

Ford uses full synthetic from the factory and has for a long time. There is no replaceable gasket it's a bead of silicone.

Denny

Aug 11, 2021 | 07:09 AM

jav_eee

Laughing Gas

Joined: May 2017

Posts: 967

Likes: 29

Quote:

Originally Posted by rvpuller

Ford uses full synthetic from the factory and has for a long time. There is no replaceable gasket it's a bead of silicone.

Denny

There sure is a gasket: Lube Locker

Aug 11, 2021 | 07:10 AM

senix

Super Moderator

Joined: Aug 2008

Posts: 37,370

Likes: 1,858

From: Frederick, MD

I use the Valvoline with friction modifier. No gasket as Denny indicated.

Aug 11, 2021 | 08:07 AM

rvpuller

Moderator

Joined: May 2004

Posts: 6,507

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From: Home Base Nebraska

Quote:

Originally Posted by senix

I use the Valvoline with friction modifier. No gasket as Denny indicated.

What silicone are you using on the cover, my DRW is getting close to a change and on my last DRW I had a problem getting something that worked.

Denny

Aug 11, 2021 | 08:12 AM

senix

Super Moderator

Joined: Aug 2008

Posts: 37,370

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From: Frederick, MD

Denny,

Will have to look a bit later as I am getting ready for a meeting

Scott

Aug 11, 2021 | 08:14 AM

nydiver

More Turbo

Joined: Jun 2009

Posts: 661

Likes: 186

From: Lakeland, MN

RTV for oil contact for sure. We've used $3 tubes of 100% GE Silicone caulk for years on gear cases...

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Aug 11, 2021 | 03:10 PM

CP Dubbs

Senior User

Joined: Jan 2021

Posts: 121

Likes: 35

LubeLocker gasket for the win.
75w140 for the rear diff.
Schaeffer or Amsoil Severe Gear is my preferred go to.
Valvoline is certainly an option,and is cheap compared to "boutique" lubes.
You could put on the factory optional aluminum cover if your steelie is getting thin from rust.

Aug 11, 2021 | 04:41 PM

#10

DoOver

Cross-Country

Joined: Sep 2008

Posts: 81

Likes: 17

From: Catskill Mountains Of NY

Quote:

Originally Posted by CP Dubbs

Do you have a part number?

Aug 12, 2021 | 05:14 AM

#11

CollinsCD

Hotshot

Joined: Aug 2001

Posts: 16,184

Likes: 398

From: Odessa, Delaware

I used Valvoline 75W140 full synthetic fluid that contains the limited slip additive with the LubeLocker gasket on my rear. No need to deal with the silicone mess and wait for it to cure before adding your fluid. Plus the LubLocker gasket is reusable too!