75w85 rear differential gear oil what are you using

[swamp2]

Appreciate the comments, esp those below. Spot on.

Also, the overall test results for both Red Line and Royal Purple were not as good as Mobil 1 and Castrol. I highlight this because both RL and RP tend to be the "darlings" in most automotive forums along with Amsoil.

It is an important highlight because it shows that off the shelf oils such as Mobil 1 and Castrol can perform as well if not better than boutique oils like RL and RP at less cost and thus there is no need to chase such oils as there is no marked difference except increased cost for less performance.

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[Dorf2point0]

Dana specifies 75W-140 in their Dana 44 Advanteks. The OEMs reduce the viscosity chasing CAFE credits (MPG).

https://fbaum.unc.edu/lobby/_107th/...dits,standard, the manufacturer earns credits.

 

[Deano Bronc]

None--synthetic oils handle heat and cold far better than conventional oils ever will.

I was planning on changing out the rear diff gear oil and putting in Amsoil 75W-90. Would you use the same in the front?

 

[CarbonSteel]

I was planning on changing out the rear diff gear oil and putting in Amsoil 75W-90. Would you use the same in the front?

Just me, but as Dana recommends 75W-140, I would run 75W-140 in the rear and is something thinner is desired in the front, then 75W-110.

 

[Deano Bronc]

Just me, but as Dana recommends 75W-140, I would run 75W-140 in the rear and is something thinner is desired in the front, then 75W-110.

Thank you. I'll order as you suggested.

 

[B_Dominant]

Is anyone still running 75w 140? Any issues?

@CarbonSteel Where did you find the DANA specified oils? I can't seem to find it anywhere.

Thanks

 

[Callelk]

Valvoline 75W-140 @ 1K

 

[Fordified1]

Is anyone still running 75w 140? Any issues?

@CarbonSteel Where did you find the DANA specified oils? I can't seem to find it anywhere.

Thanks

I run 75w 140 in all differentials. Thicker is always better for long term wear. As stated a few times earlier in the thread. The manufacturers only run the thinner oils for better fuel economy. Probably not a measurable amount for most of us.

 

[OverlandingPastor]

Is anyone still running 75w 140? Any issues?

@CarbonSteel Where did you find the DANA specified oils? I can't seem to find it anywhere.

Thanks

I found posts from @CarbonSteel before my Bronco arrived so I was prepped. At 2300 miles I changed oil, front and rear diff, and transfer case. Swapped rear diff cover when I did it. I am running 75-140w in both front and rear. About 1000 miles since that change and no problems.

 

[Sparkherd]

Dana/Advantek specs 75w140 for both front and rear axles.
Ford puts lightweight crap in there to shave a few tenths of a MPG and try to make their EPA fleet mileage requirements, which are unrealistic.
I'm more interested in keeping my vehicle for several decades, rather than shaving 0.2 MPG, so I installed 2 quarts of Mobile 1 Synthetic 75w140; $20/qt at Autozone.
I also installed an ARB diff cover which has a magnetic O-ring sealed drain plug, and a horizontal o-ring fill plug, with magnetic dipstick.
Same price as the Ford Performance diff cover.
Your mileage may vary...

 

[Callelk]

I'm currently running 75W-140 front and rear for the summer but will change to 75W-110 front come fall. I will stick with 75W-140 for the rear.

 

[CarbonSteel]

H

Is anyone still running 75w 140? Any issues?

@CarbonSteel Where did you find the DANA specified oils? I can't seem to find it anywhere.

Thanks

Every Dana Advantek axle I have seen specifies 75W-140. Here are some examples:


DS M186 Front - https://d3qx1uccksbb2n.cloudfront.net/docs/SPECSHEET-JL-FRONT-D30-42019.pdf


DS M210 Front - https://d3qx1uccksbb2n.cloudfront.net/docs/SPECSHEET-JL-FRONT-UD44A-42019.pdf

DS M220 Rear - https://d3qx1uccksbb2n.cloudfront.net/docs/SPECSHEET-JL-REAR-UD44A-D44A-42019.pdf


PS...been running it since the first fluid change in the rear--zero issues.

I am running 75W-110 in the front, but only because I had some on the shelf. When I run out, it'll be 75W-140 in both.

 

[Brian_B]

I've got about 10k on mine since switching it out to 75W140, both front and rear.

I've had the rear end apart several times in that period (working on the ELD) - no noticeable wear or issues at all.

 

[B_Dominant]

Thank you everyone! Also, just to confirm no one is running any friction modifiers with Amsoil Severe?

We absolutely have the best community.

 

[Fordified1]

Thank you everyone! Also, just to confirm no one is running any friction modifiers with Amsoil Severe?

We absolutely have the best community.

There are no clutch-packs, so no friction modifiers are needed.

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