Rear diff service

94.5 Stroker · Aug 5, 2011

Planning on changing the fluid tomarrow and installing an 08 diff cover. Was just curious what fluid I should run? Truck has almost 221k on it. I was thinking about Lucas.
Thanks Cody

Yodersstrokin96 · Aug 5, 2011

i just did mine i think it was AMZOIL 90-140 synthetic?? i wil goo look tomorrow, i have it heavy for towing alot

smokedout250 · Aug 6, 2011

I use whatever ford sells lol then I have to add some friction additive also.... I think it 75-90

lincolnlocker · Aug 6, 2011

75-140 amsoil here... that or schafers.... best you can get....

94.5 Stroker · Aug 6, 2011

Thanks guys, but will the synthetic be to hard on the seals?

chromehound · Aug 6, 2011

75-140 synthetic plus some friction modifier

My book even calls for synthetic IIRC

94.5 Stroker · Aug 6, 2011

Ok thanks, I hope ford has a diff cover in stock.

FORD7.3 · Aug 6, 2011

im running mobil-1 synthetic in 75-140 and love it, hope you have longer bolts before you start this project.

FORD7.3 · Aug 6, 2011

Forgot to add a picture and the size of the bolts, im running allen head bolts but you just need something longer, size I used was 5/16-18x1.25

94.5 Stroker · Aug 6, 2011

Ima go get those too

FORD7.3 · Aug 6, 2011

the allen heads make everything look sooo much cleaner!

444getsitdone · Aug 6, 2011

for the back axle use 75-140wt, front 75-90wt.

94.5 Stroker · Aug 6, 2011

Thanks for all the input

94.5 Stroker · Aug 6, 2011

Does the 08 cover change the fluid capacity?

cj45lc · Aug 6, 2011

94.5 Stroker said:
Does the 08 cover change the fluid capacity?

Not enough to worry about if any, BTW I used flange bolts when I did mine

94.5 Stroker · Aug 6, 2011

I have washers to use too

94.5 Stroker · Aug 7, 2011

What is the capacity of the rear diff? Also just for the knowledge how bout the D60 front axle capacity?

Pstroke96 · Aug 7, 2011

im pretty sure its 3.5 qts in the rear, plus 8 oz of friction modifier, put that in first then fill it with oil till it dribbles out the hole

gnxtc2 · Aug 9, 2011

I've heard not to use the friction modifier if the rear clutches have alot of miles on them. The modifier makes the worn clutches too slippery.

My truck has the Traction-Lok rear (204K) and only one tire spins when it starts to slip.

Billy T.
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