2004 Ford 8.8 Rear Diff Fluid?

[Ben99GT]

I've let Ultra Black cure for 24 hours before refilling, still have seepage after a couple years time.

This isn't just on diff covers either, but at the timing cover and on remote mount oil filter lines (motor oil). Dry for a year or two than all of sudden oil grime starts showing up.

Permatex is garbage compared to the Motorcraft sealants. No comparison.

 

[XJ1100]

I picked up some Motorcraft 75w-140 this past weekend...$20/qt was kind of expensive. This parts guy said the 75w-140 is all they put in these diffs now.

I have always hated sealing covers with silicon, so I searched the internet a bit and came up with a "lube locker" gasket. Google search will come up with their website.

Looks to be a reusable rubber gasket w/metal core - no additioanl sealant needed. I have one on order and will report back how well it works.

On a side note I picked up some Mercon V tranny fluid (Motorcraft) to do a pan drop and the gallon jugs say Mercov V/Mercon and Dexron III while the quart bottles just say Mercon V. I know there was soem confusion about Mercon/Mercon V so I just want to make sure that the multi spec. will be fine in my tranny?

Thanks for all the help!

 

[bdcardinal]

the gallon jugs are old stock.

 

[Bluestream]

Originally Posted By: tig1
I use Ultra Black with M1 ATF and it has worked great. 150,000 miles and no seapage at all. Have to let it set for a while before installing fluid. 2 hours at least.


M1 ATF in a Ford 8,8 rear axel??? How's that working for ya?

 

[OVERKILL]

HD apps for the 8.8 almost always call for 75w140. 75w90/80w90 are used/spec'd for lighter duty and passenger car applications.

My Mustang spec'd 80w90, Explorer 75w90 (back spec'd to 75w140 probably), both our Expeditions spec 75w140 for the rear diffs, 75w90 for the front (also 8.8's).

I have the Motorcraft fluid in mine right now. Diff cover is leaking though (Permatex was used, I dislike Permatex, but that's what we had) and so Ford Grey will be used on it shortly.

May try the Redline or AMSOIL diff fluid this time.

 

[Bluestream]

I used Permatex Black on mine with no issues. I let it cure overnight though

 

[tig1]

Originally Posted By: Bluestream
Originally Posted By: tig1
I use Ultra Black with M1 ATF and it has worked great. 150,000 miles and no seapage at all. Have to let it set for a while before installing fluid. 2 hours at least.


M1 ATF in a Ford 8,8 rear axel??? How's that working for ya?


I posted on this thread, but the M1 75-90 has worked well. Maybe 150,000 miles and doing great. My sons Ranger has it in his as well for 333,000 miles and has never had a problem. After 130,000 miles the oil was changed and it was remarkably clear.

 

[OVERKILL]

Just picked up a tube of TA-29 for my dad's diff fluid change.

 

[wgtoys]

Mobil-1 75W-140LS seems to work well in these based on helping my buddy change his out a few months ago. It is generally available at most auto parts stores and already includes limited slip friction modifiers, so you don't have to add the special sauce if you have a limited slip diff. The Mobil-1 version is around $15 per quart, slightly cheaper than the dealer stuff.

Like others have said, Ford back specified many of their rear diffs for 75W-140 synthetic even though the original tag may have said 75W-90.

I took the diff. cover to our local NAPA store and was able to get a gasket which matched up to it perfectly. I've seen too many silicone only jobs leak after a few years. If you do go with silicone only, get a premium version like Permatex's "Right Stuff" or the Ford factory sealer. Not all silicone RTVs are created equal.

 

[Colt45ws]

Originally Posted By: Bluestream
Originally Posted By: tig1
I use Ultra Black with M1 ATF and it has worked great. 150,000 miles and no seapage at all. Have to let it set for a while before installing fluid. 2 hours at least.


M1 ATF in a Ford 8,8 rear axel??? How's that working for ya?

Some transmissions use RTV pan gaskets. I know the 5/45RFE in my step-mom's '04 Dodge Ram uses only RTV.

 

[Ben99GT]

Originally Posted By: OVERK1LL
May try the Redline or AMSOIL diff fluid this time.


I just put Amsoil Severe Gear 75W-140 in my Dad's '02 PSD. Seems to be working well, no chatter (Trac-Lok) without any friction modifier added.

I wanted to go with RedLine 75W-140, but the truck developed a pinion seal leak and it needed fluid ASAP... and we have a local Amsoil dealer.

 

[01rangerxl]

I guess I better keep an eye on the Permatex Ultra Black on my diff cover. So far it is dry, but it has only been on there for a little less than a year. A dealer used Ford gray on one of my old trucks and it started to leak after a couple months, but that may have been the dealer's fault. The factory silicone on both of my trucks with 7.5 axles was black, but I have no idea what my 8.8 equipped Explorer had from the factory.

 

[Ben99GT]

Every 8.8 and 10.5 I have seen in the last 10 years came with gray from the factory. TA-29 dries a really dark gray, and could be confused with black at a glance.

 

[bdcardinal]

Originally Posted By: Ben99GT
Every 8.8 and 10.5 I have seen in the last 10 years came with gray from the factory. TA-29 dries a really dark gray, and could be confused with black at a glance.


and every 7.5, 8.8, 9.75, and 10.5 ive seen has had black used.

 

[Ben99GT]

Just to confirm, called my buddy (Ford Senior Master) and he also said all of the rear ends he rebuilds comes from the factory with gray. I might get him to chime in here since this is at least the second time this has come up.

 

[bdcardinal]

Originally Posted By: Ben99GT
Just to confirm, called my buddy (Ford Senior Master) and he also said all of the rear ends he rebuilds comes from the factory with gray. I might get him to chime in here since this is at least the second time this has come up.


K, just asked a bunch of techs and they say they've seen both on brand new cars.

 

[Ben99GT]

Ok, just went and pulled this off of my F150's 8.8 diff cover. It's OEM (cover has never been off)...and gray:

 

[Ben99GT]

Originally Posted By: bdcardinal
Originally Posted By: Ben99GT
Just to confirm, called my buddy (Ford Senior Master) and he also said all of the rear ends he rebuilds comes from the factory with gray. I might get him to chime in here since this is at least the second time this has come up.


K, just asked a bunch of techs and they say they've seen both on brand new cars.


Well, I guess that explains it.