Differential Fluid Change

[CHSurvivor]

Noticed mine is seaping. Want to dump the fluid and add some fresh fluid.

Any tips? Use dealer only?( i can check manual....is it now 80/90?)

Use dealer fluid? Is there a posi additive to use?

Is diff cover gasket same as Vic?

Thanks again fellas :):bows:

[fastblackmerc]

Noticed mine is seaping. Want to dump the fluid and add some fresh fluid.

Any tips? Use dealer only?( i can check manual....is it now 80/90?)

Use dealer fluid? Is there a posi additive to use?

Is diff cover gasket same as Vic?

Thanks again fellas :):bows:

Depends on how handy you are.

Recommended fluid is 70w140.

Most synthetic fluid has the friction modifier added.

No gasket, use RTV in place of gasket.

[RubberCtyRauder]

^^^^what FastBlackMerc said

[babbage]

Have Serge do it for you! :)

Jack up car, put jackstands on frame on each side under rear doors.
remove diff bolts - pry off cover with flat blade. Gear oil smells really nasty...

Clean cover till you can see you face in it on both sides!

Fill plug is top rearside of differential. Squirt some in to flush out all old oil before installing cover...

There are a bunch of write ups (videos) for this process.

[RF Overlord]

Make sure you can remove the fill plug FIRST.

75W-140 synthetic is the current recommendation. Brand is irrelevant. Check the label for an "LS" symbol; if you see that you don't need to add any additional FM.

I use Victor Reinz gaskets...no messing about with RTV goop.

[Marauderjack]

I'd be trying to figger out why it's "seeping" and fix that before a fluid change....new fluid will not stop a leak!!:shake:

[Comin' in Hot]

IMPORTANT INFO:

Before you pry the cover off remove the fill plug, the last thing you want it to remove the cover and have no way to fill it. It's located on the differential housing facing towards the front of the car on the driver's side.

[ARodmarauder]

Make sure you can remove the fill plug FIRST.

75W-140 synthetic is the current recommendation. Brand is irrelevant. Check the label for an "LS" symbol; if you see that you don't need to add any additional FM.

I use Victor Reinz gaskets...no messing about with RTV goop.


I just changed mine and used 75w-140 also. And as mentioned some synthetic already have the friction modifier already added to it


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[CHSurvivor]

Its seaping from the diff cover. Perhaps the jack slipped and hit the rear cover disturbing the seal? I dont mind having to change it....Preventive maintenance is always good. :) Im thinking 1 bottle should do the trick. The diff fluid changes I have done so far is that getting the fluid is has been the hardest part.
Thanks a bunch !

[Marauderjack]

I hate seeing cars being lifted with the jack under the differential......seems like trouble in the making to me!!:argue:

[fastblackmerc]

Its seaping from the diff cover. Perhaps the jack slipped and hit the rear cover disturbing the seal? I dont mind having to change it....Preventive maintenance is always good. :) Im thinking 1 bottle should do the trick. The diff fluid changes I have done so far is that getting the fluid is has been the hardest part.
Thanks a bunch !

I believe it's more than 2 but less than 3 quarts.

[RF Overlord]

Factory service manual says 1.8 litres (3.75 pints)

[CHSurvivor]

Thanks :) very much !Supposed to be lousy weather this week, so perfect time to have at it.

[JOEMERC]

Plus 1 on not using a gasket ,I changed mine used a gasket and had some small drips from cover .Pulled it back off and used sealer now no leaks ,also I jack mine up from rear all the time just to be sure to keep some room away from the cover plus you don't have to shut off air suspension switch .Except to drain diff cover you want axle to hang down for easier access .

[fastblackmerc]

Make sure you follow the package directions when using the RTV gasket maker.

[CHSurvivor]

The owners manual says 80/90. But I bought the 75/140 and the motorcraft friction lube.
Mechanic was there at counter and said use it.
The manual also says 1.8 litres. I'll fill till it comes out at top.
Thanks again
And yes it was leaking from diff cover

[fastblackmerc]

The owners manual says 80/90. But I bought the 75/140 and the motorcraft friction lube.
Mechanic was there at counter and said use it.
The manual also says 1.8 litres. I'll fill till it comes out at top.
Thanks again
And yes it was leaking from diff cover

Owners manual was correct until Ford had the soft axle issue, then they changed it to 75w140. I believe they even had a replacement tag for the rear end that specified the 75w140.

[CHSurvivor]

This is the tag. Hope it attaches

[RF Overlord]

Owners manual was correct until Ford had the soft axle issue, then they changed it to 75w140. I believe they even had a replacement tag for the rear end that specified the 75w140.^^^This^^^

[Zim Hosein]

This is the tag. Hope it attaches

I was wondering what that metal tag was for! :confused:
Cheers CHSurvivor! :beer:


On the subject of differential fluid change, what are the part numbers for the factory diff cover and gasket? Thanks to this thread I know to pick up 75w140 fluid.
Thanks in advance! :beer:

[RF Overlord]

Factory doesn't offer a gasket...they use RTV.

Best gasket hands-down is the Victor Reinz P-27608-TC...I got mine at CarQuest...

[Zim Hosein]

Factory doesn't offer a gasket...they use RTV.

Best gasket hands-down is the Victor Reinz P-27608-TC...I got mine at CarQuest...

Okay, I'll have to order one this week; how about the diff. cover, is the Marauder one specific, or will my local dealership have a bunch in stock?

Thanks in advance RF Overlord! :beer:

[RF Overlord]

It's not a normal wear item, so most dealers would prolly have to order it. What happened to the cover on the car?

[Zim Hosein]

It's not a normal wear item, so most dealers would prolly have to order it. What happened to the cover on the car?

The tech noticed a little moisture (no drips thus far). Upon closer inspection we noticed the lower right corner (when viewed from the rear) looked a few mm's bent back compared to the lower left side. All the bolts were torqued properly and the diff. fluid was full, but just knowing about it irritates me! :mad2:

I didn't have time to check w/ the parts department when I was there since I was late getting back to an appointment! :o

I figure I would just get a quick parts list together, have all of them shipped to me and take the lot with me to the dealer later in the month, easier said than done! :(

[camelgrundle]

Get a aftermarket cover way better then the sheet metal they bent on at the factory lol.

[Zim Hosein]

Get a aftermarket cover way better then the sheet metal they bent on at the factory lol.

"Affordable" suggestions are more than welcome camelgrundle, keep in mind she's bone stock and I can't see spending ~$150 to ~$200 + for an aluminum diff. cover. :confused:

Thanks in advance! :beer:

[camelgrundle]

Google 8.8 diff cover you will find some in your price range.

[fastblackmerc]

Here you go...

Under $100 with free shipping.
http://www.ebay.com/itm/NEW-Ford-Mustang-8-8-Differential-Cover-Rear-End-Girdle-System-FastShip-A-Seller-/261013373736?hash=item3cc59c03 28&vxp=mtr

Personally I'd save up $20 more and get this one:

http://www.ebay.com/itm/NEW-Ford-Mustang-8-8-Differential-Cover-Rear-End-Girdle-System-FastShip-A-Seller-/261013373736?hash=item3cc59c03 28&vxp=mtr

These after market cover have a drain plug.

[Marauderjack]

Remove bent cover (I hate it when folks jack the rear end up under the pumpkin!!:mad2:) and place it on a flat surface......smack it with a hammer a few times and reinstall with RTV......FIXED!!:beer:

[fastblackmerc]

Remove bent cover (I hate it when folks jack the rear end up under the pumpkin!!:mad2:) and place it on a flat surface......smack it with a hammer a few times and reinstall with RTV......FIXED!!:beer:

+1 on the RTV... just follow the directions.

Normally you apply the sealer in a bead then let it "skin over" before installing the part.

[Mr. Man]

Two questions:

I received 2 bottles of Royal Purple 75w/90 gear oil and a small bottle of modifier with my Moser (think that was the company)rebuild kit. Is it OK to use this? What is the detriment of using what was originally recommended and what is apparently recommended today?

Baub (RF) is that gasket you use one of those silicone ones? I've been thinking about using one of those instead of the paper gasket that came with the kit.

Thanks in advance.:)

[RF Overlord]

Eric, the Victor Reinz gasket is cork over a steel frame. I used one on the Velvet Fog and it doesn't leak a drop.

As for the RP fluid, knock yourself out. That's what's in Mary's car.

[Mr. Man]

Thanks Baub :)

Looked up the # on Google and it took me to Autozone, they say it won't fit a Marauder, fits a Marquis so who knows.

This is the one I was thinking about. Anyone have experience with this type?

http://www.latemodelrestoration.com/item/LLR-F880/lubelocker-Mustang-88-Rear-Differential-Cover-Gasket

[fastblackmerc]

Thanks Baub :)

Looked up the # on Google and it took me to Autozone, they say it won't fit a Marauder, fits a Marquis so who knows.

This is the one I was thinking about. Anyone have experience with this type?

http://www.latemodelrestoration.com/item/LLR-F880/lubelocker-Mustang-88-Rear-Differential-Cover-Gasket

Kind of pricey...

It should work.

Looks like it mainly designed to be reused a number of times.... unless you'll be in your rear alot.... I'd either go with sealer or another type of gasket.

[fastblackmerc]

Two questions:

I received 2 bottles of Royal Purple 75w/90 gear oil and a small bottle of modifier with my Moser (think that was the company)rebuild kit. Is it OK to use this? What is the detriment of using what was originally recommended and what is apparently recommended today?

Baub (RF) is that gasket you use one of those silicone ones? I've been thinking about using one of those instead of the paper gasket that came with the kit.

Thanks in advance.:)

You'll probably need another bottle of fluid. Factory recommendation is 75W/140 so you should be OK.

[Mr. Man]

Kind of pricey...

It should work.

Looks like it mainly designed to be reused a number of times.... unless you'll be in your rear alot.... I'd either go with sealer or another type of gasket.
I'd hunt to find it cheaper but I like the idea of the triple seal and it's not messy. I like to peek in every 50K or so. Last time just used a OEM style. Going to pick up a new Ford Racing girdle for MS.D's car and just thought 'why not' can't take it with you.:lol:
I'll pick another bottle of diff fluid so as to have enough. Thanks for the heads up.

Any word from your guy on my order as long as we are chatting on the same thread? PM me when you get time. :)


As far as the Ford 8.8 goes, is the differential universal, cars, trucks, whatever else might use it? I know there are differences in axle tube length and girdle depth, but the Ford pumpkin itself?

[RF Overlord]

Looked up the # on Google and it took me to Autozone, they say it won't fit a Marauder, fits a Marquis so who knows.
That's because the Marauder used RTV from the factory, so no gasket is listed. It does fit.


As far as the Ford 8.8 goes, is the differential universal, cars, trucks, whatever else might use it? I know there are differences in axle tube length and girdle depth, but the Ford pumpkin itself?Pumpkin is the same.

[CoreyM75]

Two questions:

I received 2 bottles of Royal Purple 75w/90 gear oil and a small bottle of modifier with my Moser (think that was the company)rebuild kit.
I bought the same kit for an upcoming gear swap. Is the Moser cover is a decent cover? I know it's kinda late to ask, but I would still like to know what everyone thinks.

[Mr. Man]

Any clearance issues between the FR girdle and the sway bar?

To help the other fella ^^^ any girdle not recommended? I suspect some of the truck girdles may have interference issues depth wise.

[RF Overlord]

I have the TA Performance one on The Blackbird and it fits fine with the ADDCO sway bar.

FWIW, TA Performance makes the FRPP girdles for Ford...only the engraving is different.

[Accumulator]

I have the TA Performance one on The Blackbird and it fits fine with the ADDCO sway bar..

I see they offer different ones for the 8.8", including Low and Super-Low Profile models.

Which one(s) clear the Addco bar?

[justbob]

Any clearance issues between the FR girdle and the sway bar?

To help the other fella ^^^ any girdle not recommended? I suspect some of the truck girdles may have interference issues depth wise.


Usually only if your lowered Eric. Even still it is just a matter of just getting 1" shorter links (or cutting an 1" off your existing bolts and spacer like I did). Doing this lowers the center of the ADDCO and clears the Ford Racing cover.


Builder Of Badassery

[RF Overlord]

Which one(s) clear the Addco bar?I have the TA-1806.

[MyBlackBeasts]

I received 2 bottles of Royal Purple 75w/90 gear oil and a small bottle of modifier with my Moser (think that was the company)rebuild kit. Is it OK to use this?

Royal Purple Synth gear oil (as most brands of synthetic) already has FM in it.

I would not recommend adding the bottle of FM to it. Too high a concentration of FM in the lube can defeat the purpose of the clutch pak.