Rear Differential Questions (Diff Cover Off)

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Jul 30, 2012 | 11:32 AM

#16

djed

Thread Starter

Laughing Gas

Joined: Jul 2012

Posts: 856

Likes: 63

From: Los Angeles/Ventura, CA

Jim,

Thank you!!! You are correct.

I called Mobil and they explained that the 140 is a heavier oil and should not be used as a substitute so it looks like I am draining the 140 later today. Ouch - another expensive life lesson.

I also called Dana-Spicer and they (1) verified the the 75-90 is the correct weight oil, (2) they recommended a synthetic oil, (3) recommnded NOTWITHSTANDING THE ADDITIVES ON THE BOTTLE that their testing showed that the friction modifier is necessary even if the bottle indicated the friction modifier was added.

Dana-Spicer customer service also noted that a proper fluid change should include jacking up the car from each side (one at a time) so that fluid flows into the axle bearings.

Thanks again.

David

Jul 30, 2012 | 12:33 PM

#17

stinson 108-1

stinson 108-1

Joined: Jan 2012

Posts: 1,015

Likes: 8

From: south jersey

Cool, Glad you verified that. I remembered the weight from the last time I did mine.

Apr 5, 2020 | 10:58 PM

#18

djed

Thread Starter

Laughing Gas

Joined: Jul 2012

Posts: 856

Likes: 63

From: Los Angeles/Ventura, CA

Reviving a very old thread I started back in 2012, I have a Dana 80 on a 2001 DRW cab and chassis truck. I just referred back to the owners manual and it says the Dana 80 uses 4 liters of 75-140 Synthetic fluid. After calling Mobil and Dana-Spicer, I concluded back in 2012 that I should use 75-90. I haven't had any trouble in the last eight years but I don't put a lot of miles on the truck (maybe 20K - 30K in eight years).

Any new thoughts on the proper weight gear oil?

Thanks!!

Apr 6, 2020 | 12:51 PM

#19

FordTruckNoob

FTE Chapter Leader

Joined: Jan 2005

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From: Henderson, NV

Here are the specs.

Apr 6, 2020 | 03:25 PM

#20

Bonanza35

Lead Driver

Joined: Sep 2005

Posts: 9,399

Likes: 188

From: Norco,CA

You would be fine with the 75-140 synthetic. That's what I use with 80K on it now and it works fine. I have the Dana 80 DRW and that is what my manuel said to use. I used Amsoil but did have to add fiction modifier later. Now the front is different. But I bet it would work there to. And I tow a fifth wheel to boot.