Rear Diff Fluid

[Chard]

Hey Guys,

I noticed left rear axle seal is leaking and will hopefully get that taken care of within the next 2 weeks and just do both sides. Obviously this is a good opportunity to replace the Rear Diff Fluid, as idk if the fluid has ever been replace by its previous owners (74k in the Odo).

What type of fluid is everyone else running? so far the possible options are Royal Purple, OEM or Lucas.

[Zack]

You'll need new axles or relocator bearings. Common problem

[Svashtar]

Hey Guys,

I noticed left rear axle seal is leaking and will hopefully get that taken care of within the next 2 weeks and just do both sides. Obviously this is a good opportunity to replace the Rear Diff Fluid, as idk if the fluid has ever been replace by its previous owners (74k in the Odo).

What type of fluid is everyone else running? so far the possible options are Royal Purple, OEM or Lucas.

I just used the OEM Motorcraft 80/90W when my last axle went.

[Chard]

You'll need new axles or relocator bearings. Common problem

Axle! really ?

[Zack]

Most likely.


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[RubberCtyRauder]

80/90 weight is not correct. ford revised it to like 75/140.

if diff fluid gets on your rear brakes tben you will need to do brake job as well.

dont wait 2 weeks..yes axles and bearings very probable

[Chard]

80/90 weight is not correct. ford revised it to like 75/140.

if diff fluid gets on your rear brakes tben you will need to do brake job as well.

dont wait 2 weeks..yes axles and bearings very probable

i was planning on doing that too, already there and already apart might as well.. how can i determine if the axle and or bearings need replacing too ?

The car isnt driven daily only weekends and my idea was to start maybe tearing i apart this weekend or next (reason i said two weeks)

[Svashtar]

80/90 weight is not correct. ford revised it to like 75/140.

if diff fluid gets on your rear brakes tben you will need to do brake job as well.

dont wait 2 weeks..yes axles and bearings very probable


Didn't know that, so went with the owners manual specs for 80/90. Thanks for the update.

[RF Overlord]

80/90 weight is not correct. ford revised it to like 75/140.what RCR said^^^

Ford changed the spec from 80W-90 conventional to 75W-140 synthetic when they came out with the axle TSB.

[RubberCtyRauder]

i was planning on doing that too, already there and already apart might as well.. how can i determine if the axle and or bearings need replacing too ?

The car isnt driven daily only weekends and my idea was to start maybe tearing i apart this weekend or next (reason i said two weeks)

replacing bearings is cheap insurance, have to pull axles and look for a groove worn in where the bearing rides. they are c clip axles so you have to get into differential to get to c clips

[Svashtar]

what RCR said^^^



Ford changed the spec from 80W-90 conventional to 75W-140 synthetic when they came out with the axle TSB.


Good to know, thanks.


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[Zim Hosein]

what RCR said^^^

Ford changed the spec from 80W-90 conventional to 75W-140 synthetic when they came out with the axle TSB.



While I do not disagree w/ your statement RF Overlord, my rear diff. has the silver tab w/ the new fluid rec., do you or anyone else know if "Oasis" has been updated for our vehicles? :confused:

[Svashtar]

While I do not disagree w/ your statement RF Overlord, my rear diff. has the silver tab w/ they new fluid rec., do you or anyone else know if "Oasis" has been updated for our vehicles? :confused:


I think everything's been updated with the new spec; I was curious and checked an invoice from my mechanic from back in 2009 and he used the 75W-140 back then when he worked on the rear end. I just hadn't paid attention.


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[fastblackmerc]

I think everything's been updated with the new spec; I was curious and checked an invoice from my mechanic from back in 2009 and he used the 75W-140 back then when he worked on the rear end. I just hadn't paid attention.


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Pencil in the correct info in the owners manual.

[Svashtar]

You bet, already done!


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[fastblackmerc]

While I do not disagree w/ your statement RF Overlord, my rear diff. has the silver tab w/ the new fluid rec., do you or anyone else know if "Oasis" has been updated for our vehicles? :confused:

You got the new tab / info if you have the axle(s) replaced. Ford sent the dealerships the current spec and everyone stopped using the old spec fluid. Oasis would be updated if you had the rear end service or the axle TSB applied by a ford dealer.

[Chard]

i should of added this in the original post, but whats the recommended amount of fluid per the rear diff service ?

[RubberCtyRauder]

until it comes out fill hole on a level surface really, more than 2 qt, i think less than 3? sorry dont have exact.

[Chard]

until it comes out fill hole on a level surface really, more than 2 qt, i think less than 3? sorry dont have exact.

Great! Thank you very much.

[Fly007]

Amsoil severe gear 75w140 takes just over 2 qts, put a bottle of Amsoil Slip Lock Limited Slip Friction Enhancer in with the first bottle. If you don't have a local Amsoil Dealer you work with you can order from www.mcautomotive.myamsoil.com sign up as preferred customer and you get all products at Dealer cost.


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