Both front and rear diffs take 75W140 sythetic, rear with a friction modifier of course. For the Motorcraft fluids it should run you around $90 for both front and rear diffs.

 

$90

Synthetic GL-5 meets the specs.

Service performed in my shop, $30 per axle

 

O well. ****s Motorcraft. What do you expect. Might get some pics tomorrow while I'm changing it. Maybe

 

Not a sign of any metal shreds....

 

I changed mine the other day because the rear cover had oil on it. Bought new oil, friction modifier and some permatex. Well I completed the job and it's leaking again. WTF !! I wish I could buy a Gasket, but ford doesn't sell one. Anyone have a recommendations on how to seal the damn thing so it wont leak?

 

The service generally uses RTV gasket maker. Common mistakes are: bent cover, gouged case surface (commonly done prying the cover off with a sharp instrument), applying RTV to unclean surfaces, not applying RTV appropriately (usually around bolts), and not letting RTV cure before adding lube.

 

I used some quick setting GM gasket adhesive. I put a small bead around cover, made sure both surfaces were bone dry and cleaned them with brake cleaner, put it on, tighened bolts, waited 20 mins for it to dry, than filled it.

Make sure you DONT over fill it. Thats what causes leaking also

 

Well I just finished the job again and waited about 20 minutes before adding oil. The son of a bitch better not leak this time. Getting the oil in is a major pain in the ***. What a freaking mess !! I just used brake cleaner over the whole cover and surrounding area to get it nice and clean so I'll be able to detect any leaks. Got my fingers crossed because this **** is getting expensive.

 

I should have said you should of laid the cover on a flat surface to see if there were any bends or warps in the cover it self. What kind of gasket material did you use??? Mine was a quick setting and only took about 20 mins, but other can take up to an hour and a half to set!

 

I know its a little late, but the method that worked for me was to apply the RTV on the pumpkin and let it set for 10 min. Apply cover hand tight and let set for another 10 min. Torque cover to spec and let set for another hour before adding fluid. You can drive from there, or you can let it set for more time. I do mine at night before going to bed, so it sets for another 8 hours atleast before its gets driven. Did my Expy, Mustang, and friends F-150 this way and none have yet to leak.

Also, another tip. If You look on top of the pumpkin, you will see an electrical connection. This is the ABS sensor, remove the 10mm screw that hold it on and you can fill from the top once the sensor is pulled out. Remember to still remove the side plug, so you do not over fill.

 

My front diff is spec'd for 75w90 syn..... The 75w140 is for the rear diff....

Mitch

 

They changed it. I got my fluids from a GM world class tech so he got all the updated info about my truck direct from a ford manufacturers spec cataloge. I told him that to, then he said they changed it, now they both tke 140

 

Im thinking of changing mine. Where do you get the friction modifier at? I was goign to use the 75 140, either the wally world stuff or the valvoline thats $16 a bottle

 

Either a Ford dealer or an auto parts store.

About $6-8 for the small bottle. Remember, it's is only needed if you have limited slip. An open axle doesn't need it.

Steve

 

Follow Up !!

Well,....I replaced the fluid, prepared another gasket for the rear and buttoned it all back together. IT'S STILL LEAKING !! When I relaced it this time I did a very careful look at the cover to make sure it wasn't cracked or anything because it was appearing to me that the leak was coming through the cover itself. Well I called a friend that owns a repair shop and told him about the leak and he said it is the cover itself. He's replaced alot of the rear covers because of this condition. I will say that my cover was very very rusted.

I'm replacing my cover and oil again on Monday.