Changing rear axel fluid

[pugsy]

Hey guys. The Ford manual says to change the fluid in the rear axel to just pull the plug, suck it out and refill. Would it be better to pull the diff cover off so that it fully drains (and to get out any metal filings) and then put on a new gasket and bolt it back up then refill with fresh fluid? By the way, what is the stock OEM fluid viscosity to use to fill?
Thanks

 

[Maniak]

Hey guys. The Ford manual says to change the fluid in the rear axel to just pull the plug, suck it out and refill. Would it be better to pull the diff cover off so that it fully drains (and to get out any metal filings) and then put on a new gasket and bolt it back up then refill with fresh fluid? By the way, what is the stock OEM fluid viscosity to use to fill?
Thanks

The order I would do it is the following..

1: Take the fill plug out (to make sure you can actually get it out)
2: Take the Diff cover off and drain all the fluid (you definaly won't get it all out with suction.. not much room between the gear and the housing to get a hose in there)
3: Clean the mating surfaces
4: install gasket/cover
5: fill fluid and put plug back in..

I've heard of people having issues getting the fill plug out, so take it out first to make sure you can actually get it out to put fluid in when your done.

 

[msmith65]

I did what Maniak suggests, plus I sprayed down the exposed gears with brake cleaner to get all the varnish off.

Make sure you follow #3 carefully and don't overdo the sealer. You want just enough to seal the gasket, not to make blobs that squish into the housing.

You may need some plastic tubing and a lot of patience to get the new fluid in. I used clear plastic so I could see the stuff going in.

 

[mikeinri]

It is best practice to remove the cover, because that also allows you to better clean inside, and to inspect the gears, etc. for damage.

This is especially important if you've exceeded the recommended mileage on the fluid service, particularly if by a lot.

If you keep up with the fluid at the recommended intervals, it probably wouldn't hurt anything to just do the pump method occasionally.

Having said that, I'm not a good role model. I've never had any of the 4x4 fluids changed in 263,000 miles, except one time when I had a bad rear wheel bearing, which required opening the rear diff to remove the axle.

Mike

 

[Tony H]

80-90 gear oil nothing special.

Yes make sure the Plug comes out first.

 

[pugsy]

Thanks...yep, always important to get the fill plug out before you drain!!
What's the sealer? There would be a gasket I know, but what is this sealer (brand, type, etc.)?
80-90 gear oil? Is that the viscosity? Isn't it like the XX W XX like motor oil viscosity?

 

[ricco750]

Thanks...yep, always important to get the fill plug out before you drain!!
What's the sealer? There would be a gasket I know, but what is this sealer (brand, type, etc.)?
80-90 gear oil? Is that the viscosity? Isn't it like the XX W XX like motor oil viscosity?

Yes, that's the viscosity...and if your differential is a limited slip type, be sure you add 4oz. of Traction-Lok Lube...your parts store will know what it is.

 

[410Fortune]

black silicoln works fantastic for sealing up the diff cover, there is no gasket from the factory but parts stores do sell an 8.8 diff cover gasket, I have had to use the gasket before to seal up a leaky 8.8 (metal is *****ed up a bit)

You should also check that the gear case breather tube is clear of obstructions as part of the rear diff service. Basically there is a rubber hose that acts as a vent tube for the rear axle, pull it off the axle and blow through it, I have found a few of these suckers clogged with dirt, no vent = heat builds up, air expands and cant escape = leaks develop at the wheel bearings/grease seals.

You may also want to jack the front of the truck up a bit to allow a bit more fluid to drain, also for best results let the silicoln dry before re-filling AND a $8 hand pump can come in real handy trying to refill the diff.

 

[Mic_]

also be pulling the cover you can wipe the magnet clean....

 

[ProjectAviator]

I did a diff fluid change this week. piece of cake. it how ever was tight putting in the fluid, Ford could have designed it better. Used Ford synthetic 75w-120 lsd additive. cleaned all the varnish and crap with brake cleaner. All in all about a 2 hour job.

Tim