Pinion seal replacement + diff fluid question

[George Hill]

Replacing the pinion seal in the car and you will lose essentially 0 fluid, basically what is just splashed into the recess of the seal.

Replacing the output shaft seals in the car and again the fluid loss will be very minimal.

Removing the diff and standing on the pinion you can change the diff cover without draining the fluid.

[Cronenberged]

About to replace pinion seal on my diff, and having not done it before - do I need to drain the fluid in order to change it? I just did the fluid change like, 1000 miles ago, so would hate to discard perfectly good fluid.

If I do - is the Castrol 75W-140 SAF-XJ + FM still the way to go? Or is there something better out there (aside from super overpriced OE fluid)? Thanks!

I put Amsoil 75w-140 in my diff. I don't have any whining noise but they also have a diff additive if you want to add that. Also the rear of my car is naked and I haven't heard any noise since switching.

[TexaZ3]

Quick question - pinion nut size - 30 or 32mm? And do I need thin wall socket, or regular would fit?

[mtpktz]

https://www.amazon.com/Ford-XL-3-Fri...3912613&sr=8-4

You need to mix 4.6% which makes it about 48 ml per liter. (1048*4.6% = 48)

Thanks Alex!

[TexaZ3]

Thanks for the heads up. Which FM do you use?

https://www.amazon.com/Ford-XL-3-Fri...3912613&sr=8-4

You need to mix 4.6% which makes it about 48 ml per liter. (1048*4.6% = 48)

[mtpktz]

I think BMW fluid is Castrol SAF-XJ + FM, so safe to say that's probably is the way to go. Amazon has SAF-XJ on sale right now for $25 per liter.

Thanks for the heads up. Which FM do you use?

[TexaZ3]

Does everybody recommend Castrol + FM? Or something like LiquiMoly + FM?

I think BMW fluid is Castrol SAF-XJ + FM, so safe to say that's probably is the way to go. Amazon has SAF-XJ on sale right now for $25 per liter.

[mtpktz]

Does everybody recommend Castrol + FM? Or something like LiquiMoly + FM?

[M3GA]

Forgot to mention that the diff would be out of the car and tipped towards the front seal.

Yeah u could do that or stand it up safely, cover upwards.

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[Slideways]

Need to drain fluid if messing with the diff cover.

Last year I removed the diff, pain in the a$$ job and replaced pinion and axle seals and front bushing. Then a few weeks later pressed out the bushings in the diff cover, top bolts were a pain while diff in car but doable. Used new paper seal, but u can use gasket maker.

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Forgot to mention that the diff would be out of the car and tipped towards the front seal.

[M3GA]

Is it possible to replace the diff cover while leaving the fluid in the unit? Any chance of fluid leaking out of somewhat older front or side seals?

Need to drain fluid if messing with the diff cover.

Last year I removed the diff, pain in the a$$ job and replaced pinion and axle seals and front bushing. Then a few weeks later pressed out the bushings in the diff cover, 2 rear and top cover bolts were a pain while diff in car but doable. Used new paper seal, but u can use gasket maker.

Sent from my SM-G960U using Tapatalk

[Slideways]

No need to drain fluid, though check level when done. If removing the diff to replace pinion seal, know that there's a weep/breather hole in the back cover. So if u stand up the diff (pinion facing up) fluid will leak out.

Ask me how I know 🙄

Sent from my SM-G960U using Tapatalk

Is it possible to replace the diff cover while leaving the fluid in the unit? Any chance of fluid leaking out of somewhat older front or side seals?

[TexaZ3]

No need to drain fluid, though check level when done. If removing the diff to replace pinion seal, know that there's a weep/breather hole in the back cover. So if u stand up the diff (pinion facing up) fluid will leak out.

Ask me how I know 🙄

Sent from my SM-G960U using Tapatalk

Thanks, no - not taking diff off. Will make sure to top off!

[M3GA]

No need to drain fluid, though check level when done. If removing the diff to replace pinion seal, know that there's a weep/breather hole in the back cover. So if u stand up the diff (pinion facing up) fluid will leak out.

Ask me how I know 🙄

Sent from my SM-G960U using Tapatalk

[sapote]

About to replace pinion seal on my diff, and having not done it before - do I need to drain the fluid in order to change it?

Look careful to see if the pinion shaft is located higher or lower than the diff oil filling hole. I think it is higher or about the same.